He is first seen when Lip and Ian visited him after their grandmother Peggy Gallagher claimed Jerry owes five thousand dollars to his mother who asks Lip and Ian to tell him to pay it back or she'll have her ex-husband visit him.
Jerry was unaware who the boys were until he was informed both were his brother Frank's sons, making them his nephews which shocked him. Realizing they want something, Jerry then ran back inside his house. Lip and Ian were shocked their father had a twin and tried to connect with him since he was family. However, Jerry threatened to shoot his nephews with his shot gun if they didn't leave and they quickly complied.
- A Jailbird, Invalid, Martyr, Cutter, Retard, And Parasitic Twin (mentioned only)
- It appeared he wasn't on good terms with his mother, since he owed her money and most likely knew she was involved in his nephews visit.
- Before she died, she sent him money.
- It is unknown if he is on good terms with his brothers Clayton Gallagher and Wyatt Gallagher.
- Ian took an immediate dislike to Jerry for his actions and didn't want him to be his potential father.
- He may work at a factory since he was wearing a uniform with his name tag.