Phillip Ronan “Lip” Gallagher (Jeremy Allen White) is the second Gallagher child and is the most academically minded. In high school he was a straight-A student. He created various money-making schemes to help the Gallagher clan survive, such as running an ice cream truck that also sold beer and marijuana. He also made money by taking the SATs for fellow students for a fee, but had to stop when he was caught by Professor Hearst, an investigator from the Educational Evaluation Service.
After testing Lip in private, Hearst discovers Lip is one of the statistically very rare students capable of achieving a perfect SAT score and offers him an internship at the robotics lab at the University of Chicago, which Lip turns down. Hearst gets Lip in trouble with his past clients by invalidating all of their SAT scores, since they didn’t actually take the tests themselves. In addition to being adept scientifically, Lip is multilingual; in season 2 he exhibits knowledge of Portuguese and Italian and in season 4 he speaks Spanish.
Outside the classroom Lip spends much of his time drinking beer and smoking weed and eventually participates in car theft schemes with Jimmy. Lip has a strong bond with Ian and is also the first one to discover that Ian is gay. During the first season of the show, while tutoring Karen Jackson in mathematics, Lip develops a sexual relationship with her, and soon falls in love with her despite betrayals such as her having sex with Frank. Karen though, decides to marry Jody, and gives birth to a baby that is neither Lip’s nor Jody’s. Karen led Lip to believe the baby was his.
Lip then starts a new relationship with Mandy Milkovich. People may wonder the provenance of their relationship since he was with Karen for all of the first season but it is winkingly hinted in “Aunt Ginger”, the third episode of the series, that he’s attracted to her; they consummated their relationship in season 2 episode 4: “A Beautiful Mess”. They live together from season 2 until season 3; Lip briefly lived at her house and she eventually moved herself in with the Gallagher’s.
Though Mandy and Lip have an insatiable sexual relationship–he had a plethora of condoms ready when she moved in–he is annoyed with her living with him because he thinks she’s turning the relationship into a common law marriage. Lip has trepidation that he possibly got her pregnant in season 2, but in season 4 during one of their trysts, he flippantly recommends her to get off the pill and get pregnant with his baby even though he wouldn’t be around to take care of it. When Mandy discovers Lip doesn’t plan on going to college, she considers that he is wasting his potential and his chances for a brighter future. When she secretly applies to colleges on his behalf, he is accepted by MIT, among others. Lip breaks off their relationship when he learns that Mandy hit Karen with her car, an accident that resulted in serious injuries and brain damage, to keep Karen from him (he doesn’t know she threatened to poke a hole in his condoms).
In season 4, Lip begins courses at the fictional Chicago Polytechnic. He struggles to juggle his studies, his job at the cafeteria, and his family life. Lip’s new girlfriend Amanda helps him and his grades improve.
In season 5, Lip works for Tommy in construction. At Amanda’s summer home, Lip and Amanda’s father do not get along. However, Amanda’s father offers Lip an internship when they find some common ground. Lip starts to follow a changed life but is challenged when Mickey and his brothers plan to raid a café. After the raid, Mickey locks Lip out of the getaway car, leaving him to hide from the police. Despite difficulties paying for his education, Lip receives a grant and also begins an affair with a professor named Helene Runyon. Helene invites Lip into her home and her husband catches them, but condones the affair due to an apparent taste for voyeurism. Also, Lip starts losing interest in Amanda and she punches him in the face after he says their relationship wasn’t as serious as she thought it was.
In season 6, Amanda gets her revenge by posting a naked picture of Helene on Twitter. This causes Helene to get fired. Lip has trouble getting over her until Queenie uses reflexology to give him a foot massage that arouses him and “cures” his stress. Lip is also friends with an alcoholic teacher named Professor Youens until he starts drinking and Youens starts taking advantage of him. After this, Lip continues drinking and smashes up Youens’ car out of rage. Lip gets arrested but is bailed out by Professor Youens who takes pity on him and tells him he’s been expelled. Youens takes Lip to rehab and sets him up with a job for when he gets out.
In season 7, Lip is sober as well as an intern at a sketchy company that has the possibility of a future lucrative career in tech and marketing, but is soon shut down due to an FBI investigation. He then gets a job a Patsy’s Pies working for Fiona. In this season, their relationship is that of sibling rivalry. Lip believes that because his internship can lead to a 6-figure income, that he is the one who should be the breadwinner of the family and that Fiona’s job isn’t enough, which makes Fiona furiously leave the house and vow to stop taking care of everyone else. He then meets a girl named Sierra who also starts working for Fiona, they begin to become friends with benefits but soon turn into more. Youens then tries to convince Lip to go back to college, Lip agrees to go and testify to get a position back in the college but is denied because of his previous actions, and proceeded to start drinking again and has a fight with Sierra’s ex-boyfriend. Sierra then tells Lip she can’t see him anymore. Lip goes on a few benders and ends up breaking into Helene’s house whilst drunk, she proceeds to tell him to sort himself out and “move on”. He leaves weeping. At the end of the season Lip decides he wants to stop drinking and tells Sierra he’s thinking about going back to college.