Carol Fisher was the mother of Marty and Veronica, as well as the unseen Mitch, Phil, Leo and Barry. She was a guest character in the first series of Shameless, but became a main character (along with her son) in Series 2. She was a pathological kleptomaniac and a bossy and demanding woman, fond of having affairs with much younger men. Carol is also best friends with nosy neighbour Lillian. In Series 3 she found out that Lillian had an affair with her husband Malcolm in the 1960s, leading to Carol shopping Lillian for benefit fraud.
Carol is very promiscuous, often having affairs with younger men which upsets her son Marty and brings out his pyromania. She came to live in Fiona and Steve's house because her affair with Marty's best friend led to him burning her house down in anger. In Series 3, she embarked on a relationship with a man named Norman Owens who she found out to be a nudist who enjoyed public sex. She agreed to try being sexually adventurous, but when he traumatised her by urinating on her during sex he was literally chased away by her son.
Absent from Series 5, Karen revealed in Episode 1 that Carol had "fucked off with two months takings" from The Jockey, before the camera flashed to a picture on the wall of Carol which read 'Employee of the Month.'