We meet the fabulously dysfunctional Gallagher family. Dad's a drunk, Mom split long ago, eldest daughter Fiona tries to hold the family together, eldest son Philip (Lip) trades his physics tutoring skills for oral sex from neighborhood girls, middle son Ian is gay and having an affair with his married Pakistani employer at the corner liquor store, youngest daughter Debbie is stealing money from her UNICEF collection to help put food on the table, ten year old Carl is a budding sociopath and arsonist, and toddler Liam is — well, he might actually be black but nobody has a clue how. Having her handbag stolen proves to be a blessing for Fiona when handsome stranger Steve comes to her rescue. Lip is shocked to discover Ian could be gay and decides his brother should pay a 'visit' to the ever-accommodating Karen Jackson down the block. But the sudden arrival of her furious father ensures Ian's already slim chances of happiness with Karen take a severe blow. Meanwhile, Steve buys Fiona a romantic gift, but for some reason she is less than impressed with her brand new washing machine.
Drunk as a skunk, Frank has a run in with Karen Jackson's father and returns home to take it out on Ian. The next day is Friday and Frank is no where to be found, which is a bit odd since he never misses disability check day. The family starts a manhunt and panic sets in when a body is found under the El. But Frank turns up in Toronto — with no passport and no clue as to how he got there and Steve has to figure out how to get him back to Chicago.
Having blown off Steve, Fiona turns her attention to Tony the cop who's had a crush on her since childhood. After having sex in his cop car with Fiona, Tony pursues a relationship with her. Steve, however, has not given up the fight. A woman from the Office of Inspector General suspects that someone may be stealing and cashing social security checks belonging to Aunt Ginger, the Gallagher's elderly aunt who owns the house they live in. Now Frank and his whole clan must find their aunt and bring her home before the government woman comes back the next morning to interview Aunt Ginger. Ian rejects the advances of Mandy Milkovich, one of the girls in his class. So, she tells her three thug brothers that Ian took advantage of her and they set out to give Ian a beat down.
Debbie, sad and lonely after Aunt Ginger leaves, steals a little boy from a birthday party. In classic Gallagher style, the family hatches a plan to return the toddler safe and sound without attracting attention from the Chicago Police Department, who has made the kidnapping a top priority. Karen, in complete defiance of Eddie, starts to tease Frank sexually. Frank not knowing what to make of it keeps himself busy with booze, picking up SheilaÃ s meds from the pharmacy and concentrating on finding the missing boy. What began as an innocent lie for Kevin to protect himself from a hot girl ultimately becomes a proposal of marriage for Veronica.
Knowing that Kevin is already married, Fiona tries to talk Veronica out of moving forward with the marriage. After Veronica's mother dangles a cash gift for her wedding day as an incentive, Fiona and the Gallagher's pitch in to help pull off the fake wedding of the year. Steve busies himself on a hunt to steal the perfect Lexus and Fiona finds herself in the passenger seat. Ian and Kash try to take their relationship a little further, but Ian may not be ready. Meanwhile, during a routine medical disability examination, Frank learns that he has a tumor. He spirals out of control as he deals with the news.
When a letter from Carl's teacher arrives at the Gallagher home, Fiona is thrown into action to prove it's a suitable domicile for rehabilitating a delinquent. Lip has been contributing to the family bank account with proceeds from test-taking for his fellow students. His reputation for excelling at the SAT is getting around, and word spreads to some people he would rather have kept unaware. The Kash and Grab continues to get pilfered by a local hood, and Kash and Ian are both ashamed at their inability to stop it. Meanwhile, Frank's bad business sense continues to yield consequences he's unprepared to embrace.
It's time for Frank to pay the piper — specifically, the two goons who are demanding their six thousand dollars, or else. This sends Frank into a panic, requiring every brain cell to try to think of a way to get the money fast. He finally stumbles onto a risky solution that might work, provided his family helps him out. Speaking of the Gallagher family, they have their own troubles. Ian is fed up with Mickey's bullying of Kash and goes to do something about it, leading to a violent scene. Meanwhile, Fiona finally succumbs to Steve's badgering and agrees to take a night away with him leaving Liam in Sheila's protective arms. Who better, since the agoraphobic Sheila never leaves home. But what happens when Liam wanders outside the house...?
When Frank gives up drinking, Carl and Debbie enjoy having their dad back despite Lip's warning it won't last. Meanwhile, Fiona barely has time to notice Steve's suspicious behavior as she scrambles to earn money and find a better job. Kev and Veronica take in a foster kid, Ethel, and are surprised to learn she's a married member of a polygamist religious-sect. When Lip meets with a college professor, Karen begins to question the seriousness of their relationship. Ian continues to pursue Mickey. Sheila worries Frank is no longer attracted to her.
Frank has some settlement money coming his way. The only catch — he needs his ex-wife's signature on the documents. Debbie goes on a mission to find out if Steve is cheating on Fiona, only to discover Steve may not be who he says he is at all. Kev and Veronica receive a visit from Ethel's baby son Jonah... and the DCFS. Lip needs money to take Karen on a date so he turns to Steve for help. Meanwhile, Eddie reaches out to Karen and invites her to a Purity Ball.
Things don't end well when Frank's ex-wife Monica shows up, announcing her plan to take Liam. Kash catches Ian and Mickey going at it. An enraged Fiona moves out of the house and in with Steve.
Monica's return to the family reeks havoc on the Gallagher clan, leaving the children determined to find out if Frank is their real father. Fiona, disgusted with Monica, moves in with Steve next door and tests the waters of living outside the Gallagher home. Karen decides to trust Eddie and his seaming desire to be close to her when she agrees to join him at the Purity ball. Frank hits a new low when he uses Carl to stop a disability worker from tampering with his free money from the state.
Debbie convinces Fiona to get involved with her Classroom Moms where Fiona finds a new friend in the alluring Jasmine. Tony begins to unravel the truth about Steve's car-stealing business. Lip and Ian set out to uncover which of their uncles is Ian's dad.
When Frank loses his worker's compensation, he decides to teach the kids a thing or two and lets them join in his hunt for a new and dangerous job. Meanwhile, Karen's destructive, downward spiral leads her on a mission to destroy her father in any way she can.
With Tony having discovered Steve's true livelihood and threatened with jail if he doesn't skip town, Steve tries to convince Fiona to leave with him. Fiona grapples with how to get Lip and Ian out of jail following their arrest for car theft. Frank and Karen's secret is discovered and Frank must run for his life, hiding first from Karen's father Eddie and eventually, from his own son, Lip.