Deborah "Debbie" Gallagher is a main character. She is the third youngest Gallagher sibling. In the very beginning of the series Debbie is described by Frank as being "sent from the gods." However, we soon learn that description is a bit of an exaggeration. Except not by much because she is extremely mature and grounded for her age. So much so that she has trouble relating and socializing with kids in her age group.
Throughout the Seasons
Debbie is introduced as having a very kind heart and is very persistent. She places a pillow under her father's head when he is passed out. She takes Liam to school with her in the Pilot since nobody can take care of him.
She looks really hard to find Frank when he's missing in Canada in episode 2, "Frank the Plank". After his return, she talked to him about his trip and was amazed by the sights he saw while gone.
In episode 3, "Aunt Ginger", she is devastated about her late Ginger Gallagher and that she could never meet her. Debbie is the one who cares for Aunt Ginger, who is really an elderly woman that Fiona and Frank borrowed from Veronica's nursing home.
Following Ginger's return to the nursing home, Debbie steals little Casey Casden, a neighborhood boy who she takes after witnessing his father playing with him and his sister in their yard and she gets jealous. She is forced to return him to his home through a carefully devised plan to return him so nobody gets in trouble. She is a main pawn in the planning of Frank's fake funeral to outrun two men whom he owes $6,000, which is done successfully.
Next, in "It's Time to Kill the Turtle", Debbie finds her father at the park while he was struggling to stay sober. After she gives him sugar, he is excited and asks for more. Debbie loves the new sober Frank, with whom she bonds with over sugar, which he uses to escape his need for alcohol in order to get $3,000 in a medical study. Debbie is very pleased when Frank does work around the house by cooking and telling stories. However, Lip advised Debbie, Fiona, and Carl to "enjoy the moment while it lasts." While Carl doesn't understand Lip's reason, Debbie does and tells him that she will enjoy the sober Frank for the time being. She's the one who ends up encouraging Lip and Fiona to "kill the turtle" as she put it, a misunderstanding to the reference that Lip had made about Frank previously. She decides to end his attempt at staying sober after he plans to slam holes in the roof through the attic for skylights with Carl.
When Monica arrives home in But at Last Came a Knock, she's initially reluctant to accept Monica's apology, but she eventually does, until she gets serious about taking Liam, which is when none of the kids support her apology if they ever did to begin with.
In Nana Gallagher Had an Affair, Debbie watches as Monica takes over as a caretaker for the kids and scrambles at the stress of doing so but is happy to have her. At the Alibi, she is with Fiona, Lip, and Carl, as they find their father, she watches as Frank tries to shoo them away as well Fiona and Lip informing Frank that he is Liam's biological father. When Frank looks to her for help after he is criticized and punched, she shakes her head and leaves with them. At dinner, when Lip reveals that that Ian is not Frank's son, Debbie is surprised and questions if they are still related, which Fiona assures her. Debbie's question is answered as she watches as Ian goes over the test and it reveals that he is the child of one of Frank's brothers, making him both the half-brother and cousin of the family. Debbie is surprised that she has uncles while Fiona states she has three.
In "Daddyz Girl" she signs Monica up for her classroom mom's group, but since she has once again left the children she convinces Fiona to go, where Fiona befriends Jasmine Hollander. It is Jasmine who drives Fiona and Debbie to the police station when Lip and Ian are arrested driving a car Jimmy lent them, and the two spend the night sleeping in the waiting room of the police station. She's the one who discovers Jimmy/Steve's double life, something she knows is wrong and pushes very strongly despite both Veronica and Sheila telling her she should leave Fiona to deal with her own relationships. Throughout most of the season, she is either looking into Jimmy's past, visiting his house, or harassing Jimmy about the lie he's living, frequently encouraging him to tell Fiona the truth about himself.
Debbie has grown up a bit as she's running a full-fledged daycare out of her home on her own, with the money she earns going into the winter Squirrel Fund. She ends up with a stress rash, which she attributes to being from melamine-tainted laundry soap she bought at the Dollar Store. In reaction to this, Fiona forces her to throw a party, at which she invites Simon, a boy who has a crush on her whom she only invites so he'll invite Holly Herkimer, a girl several years Debbie's senior who is still in Debbie's grade and is said to have HPV, in addition to Lip, Ian, Carl, and Carl's friend Little Hank, who she has a crush on throughout most of the season, her first real crush. She goes to Lip and asks him about what he liked about Karen, so she knew what to do to make Little Hank like her. His response was that it was about pheromones, so she dressed in Fiona's clothes and went to Mandy for help with makeup.
Debbie also ends up obsessed with death after seeing the dead body of Aunt Ginger's boyfriend Harry at the end of "Summer Loving". After this traumatic event, she ends up thinking about it constantly for a whole episode and doing a hilarious rendition of #1 Crush by Garbage.
She continues running her daycare until Grammy Gallagher arrives to the house in Can I Have a Mother. Debbie is confused as to who the old woman is but is surprised to learn that she is her paternal grandmother. However, she is more than happy to keep her secrets after being handed a $100 bribe.
In the next episode, Debbie spends more time with her grandmother, who ends up spoiling her by giving her a laptop when she is sad. Debbie is delighted with this and thanks her for the gift.
Debbie is happy to have her at the house until Peggy's activities in the basement is revealed and Fiona finds out Carl was nearly caught in a meth lab explosion. As a result, Fiona kicks Peggy out and she goes to live with Frank and Sheila while Fiona prohibits her younger siblings from seeing her, to their sadness. Peggy dies sometime after and Debbie is shocked by this.
When Monica returns Debbie is more than happy to side with her, she even sneaks into the hospital to help Frank break her out of the psych ward when she signs herself in for a period of time.
It is here where Debbie seems to finally lose her liking of Frank, when he crushes her school project that she is shown throughout the episode talking about. Frank says, "It was a piece of shit anyway." Debbie takes out a pillowcase that she filled with hard soap and starts hitting Frank with it while screaming that she hates him and "to get out of her house." Later on in Season Three she is riding home from the grocery store on the bus with Fiona. She catches a full-grown man on the bus masturbating to her. She freaks out and Fiona calls the police after driving the man off the bus. While Ian, Carl, and Lip go to find a nearby pedophile to beat up, Mandy tells Debbie that she is going to teach her how to defend herself the Milkovich way. Then she gives her a weapon. While Debbie is practicing this outside, she meets Kevin's son, Dominik and hits him with the weapon. He is shown falling down in pain and Debbie interrogates him into telling her who he is. He says he might be Kevin's son and then asks if he could find something to smoke around their neighborhood. They are later shown on the playground hanging out together while Dominik asks questions about his father and Debbie asks questions about sex and if she should become a nun and never have sex. He says she's to pretty to become a nun and kisses her, Debbie's first onscreen kiss.
At one point, Debbie expresses her desire to go swimming at the city pool. Frank tells her it's a bad idea because "at the city pool there are city kids." Apparently one summer, these city kids ripped Debbie's bathing suit to which she says they were just trying to make it into a bikini. Frank then tells her that if those kids will do that to her while running through the sprinklers in her own front yard, just imagine what they might do with an entire body of water at their disposal. Ultimately, Frank will not allow Debbie to go to the pool until she is able to hold her breath for ninety seconds, saying that if she can hold her breath that long that it will be long enough for her to get out of any trouble (should she ever find herself in it). Debbie soon is able to hold her breath for over one hundred seconds, ensuring her ability to swim at the city pool. However, the type of city kids she runs into are not what Frank was expecting, they come in the form of young pubescent girls with whom Debbie attends school. They tease her for her childish one-piece bathing suit, ask her if she's a lesbian, and tell her she should "grow some tits." The next time Debbie goes to the pool she sneaks a white bikini from Fiona's drawer and adds extra padding on top with some socks. She bravely goes for a dip in the pool, and she comes back to sit at her chair and read a book. However, this moment of bravery was short lived as someone put ketchup on the chair Debbie was sitting at, and the girls scream at her, "period! period!" and everyone laughs. A humiliated Debbie rushes home and locks herself in her room and sobs. Fiona tries to console her by telling her that, "Nobody fucks with the Gallaghers." Debbie gets the courage to go back to the pool and this is where her ability to hold her breath pays off. She fills two bags with sand which she uses as a weight to hold her down. As one of the girls who humiliated her is about to get out of the pool, Debbie grabs onto her leg and holds her underwater until she passes out. She's quite happy with what she accomplished and runs back to the Gallagher house, screaming, "That's right! No one fucks with a Gallagher!"
Now having two friends who glamorize sexual promiscuity, Debbie meets Matt, a 20 year old at an arcade who she attempts to seduce only to have him reject her. Although upset, she agrees to only become friends. She finds out Matty has started to date a girl who works with him. She become jealous and tries to make the girl stay away from Matty by threatening her and putting a snake in her car. Later, she is confronted by Matty's apparent girlfriend who threatens her with a baseball bat to stay away from him. One day at school a boy in her class starts to show interest in her. He asks if they can dissect the frog together, she accepts but her friends who are interested in him want to work with him too. He shows her all the frog parts, Debbie is not grossed out but her friends are very disgusted. When he gets to the frogs heart he gives her it. Debbie is very flattered at this gesture. They hang out more that day at school and he even sketches a picture of her. He asks her if they can meet up after his basketball practice, she accepts. They then are making out and he takes off her shirt when suddenly a bunch of people pop up and laugh and take pictures of her. Matty's girlfriend is there and says that the boy that has seemed interested in Debbie is actually her step-brother and she paid him to do this. Debbie is shocked and majorly heartbroken. Matty finds out and breaks up with his girlfriend, he asks Debbie to remain friends. She accepts but is secretly more devoted than ever to get him back as her boyfriend.
Debbie invited Matty to a party where he got intoxicated after drinking Frank's booze and then Debbie rapes him.
In Iron City, Debbie finds out about Liam's admission to the hospital and has Matty drive her there. It is here where she meets her half-sister Samantha Slott and nephew Chuckie Slott who she is shocked to learn of especially when the older woman hugs her in their meeting. She is happy to find out Liam is alright and watches him being released.
As of A Jailbird, Invalid, Martyr, Cutter, Retard, And Parasitic Twin, Debbie and her siblings are taken care of by Lip and he establishes rules. She is not at all kind to her sister Sammi and nephew who have taken to living at their home, since they are basically strangers but let them stay to tend to Frank and give her a chance though warn her of Frank's real personality.
In Hope Springs Paternal Debbie gets her period but doesn't know how to handle the issue with Fiona's behavior. She is also not pleased by Fiona invading her room and destroying things, while angrily cursing her out. Along with Carl, they visit their father and Sammi at Sheila's house. Debbie soon talks with Sammi who is happy that she gave her a chance. Debbie confides in her over getting her period and Sammi gives helpful advice. Debbie thanks her for help as Sammi finds it nice to give sisterly advice and the latter starts to accept her as family since Fiona had problems.
Debbie later learns Matt has a new girlfriend and calls her to declare war. She later put a snake in the girl's car and the girl confronts her to say she accepts the challenge, since she went to far.
Debbie launches in to the world of sex. Debbie has a party and when her friend Matt (who she always wanted to be more) passes out drunk she climbs in bed beside him and after seeing his boner puts a condom on it and has sex with him - which is technically rape but Matt won't do anything about it because he is 21.
When Debbie gets her period, Fiona tries to give her advice but Debbie sees that she still has problems. As a result, she gets help from Sammi who better helps her and she starts to accept her as a sister while the latter finds it nice to give sisterly advice.
After Debbie gets into a fight with Holly and is saved by Derek she begins to show an interest in him. Debbie attends the gym that he goes to for boxing and keep fit classes and then he starts to hang out with her more and begin to like her in the same way, they begin a relationship together after Debbie creates a scene in front of the Gallagher household. Debbie meets Derek's family and she learns about this girl his parents look after who is a teen mom and intrigued by this, she also learns Derek's parents were childhood sweethearts and had a baby when they were not that much older than Derek and herself. Debbie then convinces Fiona that she should go on Birth Control while attending the clinic the nurse tells Debbie that if she is planning on having sex in the next few days she should still use a condom because the pill will not work until that long. That same day Debbie goes home and she is with Derek he goes to put on a condom before having sex she says "it's okay I'm on the pill" and they have sex. In the final episode of the season Debbie has an altercation with Fiona and she says she is pregnant. She tells Fiona she wanted to get pregnant and she knows who she loves and she knows what she wants.
Fiona hates this so she tries to convince Debbie to get an abortion. Fiona finds out she is pregnant too. Debbie is excited and says that they can raise them together. Fiona tells her that they can instead get abortions together and have babies when they are both ready. Debbie is outraged and storms off. She later goes to the clinic with Fiona but doesn't get an abortion and lies to Fiona telling her that she got one. Fiona finds out that she lied when Derek's parents come to the house to discuss the baby. Debbie believes Derek will stay with her but then Debbie finds out that Derek moved to Florida to live with his Grandparent's because he doesn't want to be a dad yet. Debbie continuously tries to contact Derek but he disconnects his phone preventing that from happening.
She still decides to keep the baby as Fiona does not approve of Debbie having this baby and tells her she will not support her when she gives birth. Debbie decides she has to find a place for her and her baby to live. With the help of Frank, she becomes a live in nanny for the couple since the mother was dying of cancer. Encouraged by Frank, she tries to seduce the husband of the dying woman so they won't fire her, he rejects her advances. Frank takes the dying woman to The Alibi to give Debbie some time to seduce the husband. There Frank finds out that the dying woman used to be a lesbian. Frank tells Debbie this and suggests that she try to seduce the dying woman. Debbie dislikes the idea but still spends time with the dying woman. One night Debbie is in her room when someone enters and gets into bed with her, Debbie thinking this is the husband says "I was hoping you'd come" when turning to see its actually the dying woman. Later on the dying woman finds out she isn't dying anymore and the cancer is almost gone from her body. Frank tells Debbie she must start sleeping with her or else she won't have anywhere to live. Debbie tries to sleep with her but then stops before anything happens telling the woman that she is actually 15 not 18 and she isn't a lesbian.
Debbie later returns to the Gallagher House after Fiona reclaims it.
On the episode Grandma Queenie to the Rescue, Debbie is shopping at a baby store when she meets a man who asks her opinion on a gift he is buying his sister. She tells him her opinion. He tells her thanks and says his name is Larry. They then meet again that same day and he asks her out for lunch. While they are deciding what to get he starts moving his foot against her leg she then says "You know I'm pregnant right? 7 months" He tells her he is fine with it. After they are done their date it seems as if they are going to kiss but then he kisses her baby bump instead, Debbie looks confused by his action. The next day Debbie is going to her baby class when she sees Larry she asks him "How'd you know I'd be here?". He tells he didn't and is there with somebody else while pointing to another pregnant woman. Debbie is very confused and he tells her that he has a baby bump fetish, where he is attracted to baby bumps on women. Debbie is disgusted telling him that "she can't believe she fell for him" he tells her they can still date. Debbie asks what happens after she gives birth. Larry responds saying that they won't date anymore but they can be friends. She also finds out that he his dating several other pregnant women but she is his only 7-month-er. She says he is a sick person and leaves the class.
Grandma Queenie, Frank, Chuckie, and Debbie move to Queen's commune where Debbie gets her own birthing tent. However, living at the commune is not all that it is cracked up to be as Debbie goes into labor and discovers that the midwife had not delivered a child in over ten years. While labor progresses, Debbie gets more and more anxious and eventually her and Frank flee the commune back to Chicago. She is worried when her father is taken by thugs and calls out to him but her water breaks. Debbie is found by Fiona and delivers her baby on the kitchen table in the Gallagher house. Debbie named her child Frances Gallagher, Franny for short, after her father Frank. After the birth the EMT arrives, Debbie and Franny leave in the ambulance alone after Fiona tries to join.
After her daughter was born, Debbie tries to prove that she does not need any help in raising Franny. Frank's crying disturbs everyone in the house. Fiona wants to help, but Debbie refuses any help or advice. Lip hypothesizes that Debbie may suffer from postpartum anxiety. She stays up all night with Franny and takes her to school too. Debbie realizes the struggles of being a teen mom when she is not allowed in class with Franny. Debbie's teacher tells her that she should go to the guidance counselor to see how to continue her studies at home and suggests next time to use a condom. After a disastrous day at school, Debbie finally lets Lip hold Franny at the bar when she goes pee. After another night of no sleep for the Gallagher family, Debbie is awake and perky offering to cook everyone eggs. Lip believes that she is going to have a major crash soon. Sure enough, while Debbie is feeding Franny and studying, she falls asleep and Franny falls onto the ground. At night Debbie is found hiding under the staircase while Franny is crying. Debbie professes to Sean and Fiona that she is a terrible mother and dropped Franny. She states that she cannot get Franny to stop crying and she cannot feed her enough. Fiona feels Debbie's head and tells her that she has clogged ducts and that warm water and ibuprofen will help out. Debbie reluctantly goes to Fiona's wedding to Sean stating that she wants Franny to be in the photos. She later joins her family and friends in throwing Frank off a bridge after he ruins Fiona's wedding. At the end, she tells Lip that they believe that their father is dead but is unsure.
During Hiraeth, a month has passed and Debbie nearly abandons her daughter but she has second thoughts. She takes her to a park and tries to talk to a fellow mother who sees that she's a teen mom and ignores Debbie. Debbie then turns around and steals the mother's luxury stroller and flips it on Craigslist, selling it for $1,500. With the money Debbie hires a night nurse to take care of Franny and begins to attend school again. This is short-lived after Debbie accidentally steals a stroller with a baby in it. Debbie goes home and is not too surprised to see that Frank is still alive after surviving the fall but voices her displeasure. Like her siblings, she wants nothing to do with her father and treats with him with disdain but still has care for him.
In Swipe, Fuck, Leave, Debbie hears Frank voice his intentions of disowning the family for their actions. She tells him that she will have her daughter go by her middle name Harriett or "Harry" to distance herself from him. Debbie also learns Frank is taking Liam, since he is the only loyal child he has. She warns Liam of their father's ways and says he is in for disappointment like she was. After a day out, Debbie goes home, only to find the walls were blocked with cement, courtesy of Frank getting revenge on his children for trying to kill him and kicking him out. Debbie was not pleased by her father's act and helped her siblings destroy the walls.
During Home Sweet Homeless Shelter, Debbie begins to steal from clothing stores, stealing hundreds of dollars worth of baby and mommy clothing at a time. After a few successful rounds, Debbie is soon caught stealing and Fiona is called. Fiona gets Debbie out of the mess by saying that Debbie is "special". Debbie is incredibly insulted, but plays along in order to avoid jail and the ploy works. Fiona chastises Debbie for being so stupid and careless, claiming that she's not thinking of Harry. Fiona tries to emphasize to Debbie that if she is caught doing this again Harry will be taken away from her and that in order for Debbie to be a good mother that she needs to be there for Harry. Fiona later lays down house law, by stating that everyone in the house, except for Liam, needs to contribute money in order to live in the Gallagher house and if no one wants to that she will sell the house and move to a smaller house. Debbie has to contribute more because of Harry's living expenses as well, Debbie fights that this is not fair, but concedes seeing she has no other place to live. She has great struggles making money since she is a teen mom without any form of graduation or classification. She is not pleased to see that her father has opened a homeless shelter in a vacant house on the block. Debbie watches as Frank turns her and the other Gallagher children (except Liam) away for their actions on him as he basks in his fortune.
As of I Am a Storm, she asks Svetlana for help in love. Svetlana suggests to find a "weak, desperate man" who could provide for her. This choice doesn't sit well with Fiona who can't help because
Her attempts at finding a partner and begging both fail miserably in Own Your Shit . With little options, she visits her father at his shelter and he is less than pleased to see her and her daughter. Debbie tries to make peace with him long enough for him to help, since she needs to learn on scamming. Frank (still holding a grudge against her) refuses and calls her a Gallagher traitor, as she makes him consider his granddaughter while offering to change her name back if he does help. He agrees and tells her to go begging, since she fits the part and people will love to help her. She later gets into a fight and is nearly arrested while she does find a solution. Marriage with a brain damaged man she found in Fiona's diner, as he has an apartment and money.
Much later in The Defenestration of Frank, she officially drops out of school but gets her GED a day later and visits her father at his shelter. She sees that he is doing well for himself and tries to make peace with Frank long enough for him to give consent though he refuses since marriage is a big deal and she lashes out at him for still being himself with a new family. She goes to Fiona and surprises her with her recent actions and asks for help but the latter is busy to help her.
In Ouroboros, Debbie is reunited with her mother who helps her in reclaiming her daughter from Derek's parents. As thanks, Debbie allows Monica to stay with her and Neil's apartment. She later goes with Monica and Franny to the DCFS meeting in order to gain custody of Franny. In the end, the official grants Debbie continued custody of her daughter provided she and her family don't terrorize the Delgado's again. Debbie is pleased after the official tells Tanya and Mrs. Delgado not to try to steal the baby again and are granted visitation rights, which they begrudgingly accept.
After Monica's death, she meets her grandfather Bill Darrgen though the latter is disappointed at her being a teen mother.
At the funeral, she gives a few words about her mother before she watches as Frank speaks about Monica and praises them for their strength. She later makes peace with her father along with her siblings to come together.
After her mother's funeral, Neil begins to think Debbie has lack of interest in him, so he tries to make himself appeal to her but nothing works as she mostly leaves her daughter in his care. Debbie has one of her friends who is a nurse care for him. She is also confused by her father's change, thinking he has lost his mind.
In God Bless Her Rotting Soul, Neil quickly falls in "love" with his nurse and promptly breaks up with Debbie while calling her an awful person. Debbie tried to warn him that the nurse was using him, though Neil said Debbie did that to him and has her leave while calling her an awful person. Not too long, she and her siblings go to Fiona for help when they are attacked by thugs led by a man named Eric Stark who owned some of the meth and threaten the family for his money. Though reluctant, Debbie and the others apologize to Fiona for not listening and all except Carl and do so. After Fiona decides to help, Frank (who had decided to change) also volunteers for help and she has him use his job to get tools. Debbie and her family are forced to dig up Monica since Fiona put her share of meth in the ground with her. They arrive at the storage unit and pay Eric, but the payment is still not enough and he threatens them as Debbie quickly guards Liam while Ian protects them. Fortunately, Frank steps in and she watches as he successfully threatens Eric to accept the payment or be faced with death if he comes near the family again. Debbie is surprised by her father's actions and leaves the area with her family.
During Fuck Paying It Forward, Debbie continues her job but is sad she is missing out on her daughter's first steps. She later helps Fiona with her situation with Sean and tries to tell her sister to forget about him. She and Carl watch as Frank bonds with Liam still trying to change himself, as both remain unconvinced at their father's change but humor him as he is putting in the effort and doing better. At the end, she watches as her daughter walks to Frank and she is happy at this sight and by her father acting as "Saint Francis"
In The (Mis)Education of Liam Fergus Beircheart Gallagher, Debbie lets Mrs. Delgado babysit Franny while she works. When she comes to pick her up, she finds out Derek has returned for his mother's birthday. A tense meeting is made since Derek had left all the caring for the baby to her. Now guilty for his previous behavior, Derek tries to make amends by offering to cover his child's needs but Debbie takes Franny and leaves in a huff.
Debbie continues her job at wielding, she is angry that she is paid less than the man because of her need the restroom. She creates a makeshift diaper to help her out and though she gets the money, she learns that its because she is the victim of sexism after being called "Jugs".
Debbie tries to stand up for her female rights meets a worker named Alex who reveals herself to be a woman that has to hide her gender. They get along and Debbie sleeps with her and moves in with her, beginning to think she is a lesbian and tells Ian about this though he tells her that she isn't. Indeed, Alex breaks it off after hearing her complaints about men and labeling her straight. Debbie returns home and complains about her venture as Carl does about his own. However, they stop when Liam's classmate Sissy decides to move in with him after telling him, she's supposedly pregnant with his child. Debbie and Carl are confused by this display before they intervened by telling Liam that he didn't impregnate Sissy, due to the timing. Debbie goes to Fiona's tenants and asks about lesbian' acts, she is aroused to Mel kissing her and flashing her. Debbie leaves amazed by the experience. Afterwards, she attends the hearing of Ian and watches as he admits to being bi-polar to get the insanity plea and shorten his time in sentencing. Later on, she and Carl have Lip who was told of Liam's situation to help and they kick Sissy out by drugging her and bringing her to a clinic.
Debbie tries to reconcile with Alex by inviting her to lunch but sees Alex is no different from her with women. She leaves while letting Alex pay for the large bill. Debbie goes home and dines with her family and an actress Lip was watching as a sobriety watcher and the latter even kisses Debbie. She is later present when Ian goes to prison for two years, she sadly hugs her brother goodbye and wishes him luck.
Debbie is woken up at two in the morning, she and her brothers investigate the sound in the attic and see its an alarm with a picture of Ian. They realize that he left them a memento and smile at the gesture. She would talk with her brothers of living arrangements and speaks up about their father needing a room. Debbie calls Fiona but she doesn't answer so she goes to her apartment and finds the bruised Fiona who informs her of her situation with Ford and her debts. Debbie takes Fiona to get her wrist treated and helps with the car by having her friend investigate it and gives them tips to collect money from the damage by saying it was stolen. Debbie watches Fiona leave but tells her friend to help her with something and goes back home where she informs her siblings of what's occurred. She lets Lip handle Fiona while she does something. Debbie goes to Alex for more help and tells her about Ford who she states did worse than the men they humiliated and she intends to punish. The trio build something that would symbolize revenge and are pleased by its foundation. Debbie arrives home and takes Fiona and everyone else to Patsy's. She reveals she had her friends help in getting revenge on Ford and Ford is hung from a sign with his pants around his legs. Debbie is congratulated by an arriving Lip before she watches as Ford begs for help to get down and Fiona shoots a paint gun at his rear end and takes amusement from the act, thanking her family for giving her the chance.
As seen in The Apple Doesn't Fall Far From The Alibi, Debbie has taken to taking over the Gallagher house while Fiona is in a drunken slump from her break-up and bankruptcy. Debbie has decided to fill in as head of the Gallagher Household, resulting in her paying the bills and setting wages for the house.
In BOOOOOOOOOOOONE!, Debbie continues to take charge and shows she is really serious by even having Liam chip in since she and Carl worked at his age. She is also worried for Fiona who is still down and gets ready to defend her when Ford comes but is turned away. Debbie later learns of her father having kids, she scoffs at this while listing herself as an example of her father's failure and calls her fault a sexually confused teen mother. She changes the locks to house and keeps both Fiona and Liam but ultimately relents to letting them back.
In Los Diablos, she continues taking control and asserts her authority of the Gallagher House. She later checks the gas meter but gets trapped in the basement and calls for help. Fortunately, Kelly heard Debbie and help get her from under the house and spanks Debbie's behind and turns off the gas to the house. Debbie is surprised by this and develops an attraction to Kelly.
During The Hobo Games, she makes fun of Carl's new job as a pirate mascot but wishes him luck as she and Kelly hang out. Kelly sends Carl a picture and he worries because of their closeness.
In You'll Know Bottom When You Hit It, Debbie defends her status with Kelly as friends to Carl but things get tense when Kelly breaks up with Carl for believing she'd be attracted to Debbie and not trusting her.
As of Lost, she helps Carl and Kelly in bringing an injured Frank in his home though pukes at his bone out. Debbie spends the day with Kelly and her daughter to go shopping for supplies with her new school.
While on the couch sleeping, Debbie sees Kelly cuddling with her on the couch. Debbie takes the chance to kiss Kelly and the latter unconsciously kisses her back until she wakes up and rejects Debbie. Kelly frantically tells Debbie they can't be together since she is straight though maintains the thought of being friends and leaves, while Debbie is devastated. After Carl gets home from work, he finds Debbie crying on the porch and asks what happened. Debbie explains she took the chance to kiss Kelly but the latter rejected her. Carl sympathizes with her over being dumped by Kelly. They reconcile before they spot Kev dressed up as Jesus carrying a large cross.
During Found, Debbie and Carl go out for revenge on Kelly and tell Fiona they'll be out. The two vandalize Kelly's truck and quickly flee the scene when she nearly spots them. She is later told by Fiona of Frank's recovery, as well as Fiona's assault being reduced to a misdemeanor. Debbie later finds Liam at the house of a friend and he reminds her of how she unknowingly gave him permission. When coming back home, Debbie speaks with Carl and hears him state that he is not going back to school and will instead stay at his job. She tries to talk him out of it but he is insistent on doing it. As Debbie goes back to Liam, she is confronted on her actions of vandalism by Kelly who she informs of what Carl is doing and goes spending time with her grandfather and she gives Frank the list. She also reveals that she hired a nurse Frank is familiar with to care for him. She goes to speak with Fiona about Liam, but she discovers is planning to leave, she tells Lip about this and agrees to her brother's list of demands. That night, the family learned Fiona already left them but threw a party for her anyway. As she watched her loved ones celebrates, Debbie discovered Fiona left 50 grand for the family, with a note telling them that she loved them.
As of We Few, We Lucky Few, We Band of Gallaghers!, six months have passed and Debbie has fixed up the house, standing as the new head of the house. Debbie is later present at the birth of her new Nephew Freddie Gallagher and congratulate her big brother and his son
In Sleep Well My Prince For Tomorrow You Shall Be King, Debbie tells Mikey O’Shea if he wants to live the house, he has to pay rent. At the end, he uncovers Debbie's scam and blackmails her into giving Frank control of the house or he'll destroy her receipts. She complies with his demands. The next day, Debbie gives her family money cards and Frank control of the house, as they are surprised with her
In A Little Gallagher Goes A Long Way, Debbie comes home and finds Frank passed out from the party. Finding his bucket of money, she promptly confiscated it in retaliation for his theft of her stuff. While at the market, she bumps into an old friend who has kids and the latter persuades her to get Derek's money for Franny. Following her advice, Debbie goes to Derek's house but gets a shocking revelation after it is revealed that Derek had died in service. However, Debbie is angry that Franny was not listed as a beneficiary, unlike Derek's other children with his wife.
During Sparky, Debbie tracks Peppa down to serve her papers but the latter evades her. After a series of events, Debbie is able to get her the papers. However, Debbie is shocked to hear that her lawyer isn't licensed and is shocked when Peppa arrives with military lawyers. Peppa agrees to share the money but only for full custody of Franny, to Debbie's shock and anger. Later, she returns home as they were making plans for Ian's party. She complains about her day, as Lip comforts her. However, Debbie's spirits are lifted when Ian returns home. Happy to see her brother back, Debbie hugs him and joins in the party.
During Debbie Might Be a Prostitute, Debbie goes with her friend to a hotel and they try to scout potential suitors until Debbie has second thoughts and looks to a woman for help. Debbie ends up hook on up with her but realizes that the lady mistook her for a prostitute.
In Now Leaving Illinois, Debbie continues her relationship with Claudia but also her fling with Julia. However, once Claudia offers the chance to work with her at her home and use one of her cars Debbie starts to feel guilt. Debbie later meets with Julia who starts talking about pursuing their relationship, despite the previous tension between them but Debbie sees how clingy she has become when the latter invite her to do a homecoming dance. Subsequently, Debbie rejects her and Julia breaks down and plays with her but Debbie maintains her stance. Later on, Debbie is tending to her daughter at home before Julia visits. Julia tells Debbie they will go to homecoming or else she would tell their mother about their relationship to Debbie’s dismay. She was later present at Lip's family announcement and comes up with several reasons why he did so but is surprised to hear that her brother Lip is moving away to the Milwaukee.
In Location, Location, Location, Debbie is at the house where she and her sibling briefly wonder where Frank is since its quiet with him gone. Later, Debbie attends dinner with Claudia while simultaneously going to Debbie's dance. She returns to the restaurant only to find Claudia gone. Realizing where she might, she finds Claudia at the dance and tries to explain before Julia appears and confessed to her mother about the affair but reveals that she was the only experimenting, to Debbie's surprise. As she and her mother argue, an exasperated Debbie walks away from the scene.
During Gallavich, Debbie is in bed with Sandy and learn Ian's wedding venue was destroyed. Debbie is further annoyed to see Julia has run away from home and decide to go to stay at the Gallagher house. Julia tells Debbie since she was indirectly responsible for this she staying with her. Debbie walks away from her and Julia talks to Sandy Milkovich who introduces herself as Debbie's girlfriend. As she comes home, she sees Julia make herself at home in Debbie's room and announces she’s going to the wedding of Ian. Debbie is annoyed until laughing Julia being punched by Sandy. Eventually, her mother calls and Debbie learns the truth but Julia only makes the situation worse by lying that she is continuing the affair. At the wedding, Debbie talks with Ian and both laugh that Frank is having a good time. Debbie dances with Sandy and has a good time. The next day, she is woken up by Carl stating the cops have shown up and wonders what their father did now. However, the cops are revealed to have been called by Claudia about Debbie's relations with Julia. Hearing this, Debbie makes a run for it with the cops giving chase while a worried Carl decides to have a talk with the confused Julia.
Debbie is a sweet, spirited, smart, kind-hearted girl. She has deep trust and loyalty towards her family, though she tends to be extremely naïve. She lived for years with the hope of having a good father in Frank, hoping he may one day change. She showed genuine concern and care for her father when no-one else did. Though, she is capable of unconditional love, she demanded love from Frank in return, only to be disappointed by his selfish, uncaring nature. When asked if she ever wished Frank dead, she confirmed it. Debbie has, or at least had, a great deal of respect, trust and love towards Fiona, who was her closest sibling and only sister. She always supported her in house and often took care of Liam.
She is greatly mature as she could explain a confused Carl how lesbian sex works in season 1. She holds great resentment for her mother for leaving, even despises her. This is evident through Debbie, when she first saw Monica in several years, pushing her away and running home, as well as her attempts to take Liam and "start her own family". Though her hatred is lesser than Fiona's, due to Debbie's last days with Monica being of a mostly positive nature since she helped in getting her daughter back. She loves Liam deeply, whom she spends most time with, and began to cry when Monica announced that she wanted to take Liam with her. She was upset about her great aunt's death, despite never meeting her.
Her relationship to Frank is very complicated. It shows her ability to daydream at her maximum when she tolerated him most, as well as doing little acts of kindness like putting a pillow under his head when he's passed out, or making him breakfast. She never receives more than a smile from him, and only when he's in his rare sober states. This frustrates her to the point where she stole a baby that had a father who plays with him out of envy. She prayed for his safe return when he disappeared and even posted pictures of him at their house's fence, or hugging him tight at his return. She tried to talk and play with him, even when he expresses open disinterest. Her concern for her father ultimately died, when Frank destroyed her school project, calling it "a piece of shit". She had a frustrated rage in which she beat him with a bag of soap, screaming in sadness and frustration. Afterwards her relationship to him cooled down, once she finally understood that Frank will never change. Though, she continued to spend time with him, she lost most of concern for him but still loved him when she told him after his liver failed. After he supported her in her pregnancy, she was grateful and named her child after him as gratitude even calling him "Dad" again. When he ruined Fiona's wedding, she took part in throwing him off a bridge for it and casually told Lip that she believed Frank dead. After seeing that Frank survived being thrown off the bridge, she was not pleased and showed him nothing but contempt in his moment of pain. She went as far to rename her child to distance them from him and warned Liam of the disappointment he was in for with Frank. She was also annoyed by him getting revenge on the family for their acts and treatment. Despite that, she would attempt to reconcile with him, for she needed his help when risking losing her home and child. Although he refused, she got him to comply by changing her daughter's name back and he gave her advice. The next time she went to him they argued, she let him stay with her and her boyfriend along with Monica. Debbie was also moved by Frank calling her and her siblings strong, with them making amends. She was very surprised when Frank decided to genuinely change in Season 8, though she was put off by his new actions. She was speechless at him defending her and her siblings from a meth head by threatening the man with death if he came near them again. While she was grateful, she still believed that he couldn't truly change himself but humored him as he went on and smiled at his progress as he was doing better. When he injured his leg, she was forced to care for him along with her siblings and was annoyed by his complaining. She loudly told her father that nobody loved him, but this was far from true as she had hid his medicine from him, let him watch her daughter, and found a caretaker to tend to him, showing Debbie was just irritated by his whining and does love him.
In her teenager years, she grew obsessed with boys and sex, probably an influence of living in a house hold with her extremely sexually active siblings, mainly Fiona.
She has darker, reckless, manipulative and arrogant sides to her personality spectrum as well, and lived out delusion, cynicism and frustration. She happily kept her grandmother's secret of a gun and finger after being bribed. She also tried to prevent Fiona from discovering their grandmother's meth lab. She doesn't take no for an answer, as after her first boyfriend refused to have sex with her due to difference in their age, she took advantage of him while he was drunk and had her way with him. She expected him to be fancy with her afterwards, though it clearly contradicted his prior behavior. Her second boyfriend was in her age and they understood each other well, yet she drifted into a daydream again. She grew obsessed with creating her own "happy family" with him (Once again being extremely delusional, naive and arrogant) , the total opposite of her own family, she grew up with and started resent. She recklessly tricked Derek into making a baby with her, without asking his opinion or permission, or even knowing his own dreams and desires. This might be her most selfish act, as she casually changed the lives of them both, simply out of her own desire to have a family and expected everyone to simply play along. But she loves her daughter regardless of her unfulfilled dream, even if Franny means that she will have to live out an unsatisfied and unfulfilled existence because of her. She has great resentment for Derek for abandoning her and destroying her delusional dreams, and shows little understanding for his personal motives, calling him a "deadbeat". Her relationship with Fiona is somewhat cold, as she lets her frustration out on Fiona, resenting her for her selfish nature once the children are older. She is also unhappy with Fiona who repeatedly told her to give up her pregnancy. Debbie begins stealing to resell valuable goods to care for her baby.
In season 9, Debbie starts to explore her sexuality. She met Alexandra while she was protesting fair wages for all genders. The two hung out and soon they developed feelings for each other. This was something new to Debbie as she never really had any interest in girls. However, she continues the relationship with her despite how confused she was. She asked Ian how he knew he was gay. He said he knew because he was having sex with a man. When he asked her why she tells him that she might be gay. Ian instantly scoffs and tells her she's not gay. The two talked but by the end, neither of them had any more of a clear mind. After just spending a few nights with Alexandra the two decide to move in. This showing that the two are high on love. However, after the two talked about their past, it becomes clear to Alexandra that Debbie is not over guys and that she is not sure if she straight, bi, or a lesbian. Debbie tells Carl that she's in love with a girl. Carl also does not believe that Debbie is gay because she has a baby. Debbie tells him that plenty of lesbians have babies. By the end of the day, Alexandra calls it off. "I can't do this anymore, there are too many triggers. I can't fall in love with another straight girl" Alexandra says. Debbie claims she's gay but Alexandra fights back saying for what 2 days. The two break it off and Debbie goes home crying. When her family asked what was wrong she tells them that she and Alexandra broke up. The family, however, had no idea who Alexandra was or the fact that he was actually a she.
Throughout the season Debbie explores her sexuality all while trying to take care of her family. Carl starts to date Kelly and brings her home several times. At first, Debbie doesn't think much of her, just her brother's girlfriend. However, over time the three of them start to hang out a little more. This causes Debbie to develop feelings for her. One day Kelly had fallen asleep on the couch and Debbie finds it beyond cute. She decided to kiss Kelly most likely thinking Kelly wouldn't know. Kelly woke up surprised to see Debbie kissing her and not Carl. She tells her that she's not gay and that she never meant to lead Debbie on. By Season 10, it appears Debbie moved onto a new relationship will be with a woman named Claudia who mistook Debbie for a prostitute until learning otherwise. After overcoming some awkwardness because of the error, the two were able to be a couple. However, things took a turn when Debbie developed a mutual attraction to Claudia’s daughter Julia and they ended up sleeping together. Once Julia was revealed to be using her to spite her mother, Debbie found a new relationship in Sandy Milkovich.
- She is one of the few Gallagher children to call Frank "Dad".
- She is the second of Frank's children to have a child, with the other being her half-sister Samantha Slott.
- Coincidentally, Debbie is the youngest of Frank's daughters while Sammi is the oldest.
- According to Frank, Debbie's first steps were of her running to her mother at the police station for the latter's first booking.
- Like Fiona, she earned her GED but got it quicker than the latter.
- She is missing some of her toes after her foot was crushed.
- She is a rapist, as she date raped her first boyfriend Matt after he became incapacitated from drinking Frank's homemade beer. She doesn't feel bad about the rape as after she proudly yelled "I am a woman!". She only feels bad that Matt broke up with her.
- She is bi-curious, due to her wandering interest in both sexes.
- She is closest to Fiona, Carl, and Liam out of her siblings.
- She has had three real boyfriends.