Shuggie Bain
Shuggie is the novel's protagonist. The youngest sibling in a family of three children, Shuggie is Agnes’s child from her second marriage to Big Shug. Shuggie is a target of bullying due to his feminine behavior and apparent homosexuality. He aspires to be a hairdresser and hopes to attend a hairdressing school. As a child, Shuggie is left with the responsibility of taking care of his alcoholic mother as other family members abandon them one by one. He loves his mother unconditionally and goes to great lengths to defend her dignity and protect her, but ultimately decides he cannot save her from herself, allowing her to die by inhaling her own bile.
Agnes Bain
Agnes is an alcoholic mother with three children from two different marriages. She is a beautiful woman who takes pride in her appearance, maintaining a glamorous persona even though she is poor. Agnes's volatility worsens with her drinking, and she alienates her daughter and eldest son. Although she achieves a year of sobriety by attending AA, she relapses when Eugene pressures her to take a drink. Shuggie tries to take care of her when she has no one left, but he eventually lets he die by inhaling her own bile.
Big Shug
Big Shug is a Protestant taxicab driver and the second husband to Agnes, and Shuggie's father. Even though Agnes left her first husband for a better life, Big Shug turns out to be a womanizer and an abuser. His flagrant infidelity drives Agnes further into drinking and volatile self-destructive behavior. Big Shug abandons Agnes and Shuggie to live with Joanie Micklewhite, a cab dispatcher. He has four children from his first marriage but abandoned them to be with Agnes.
Catherine
Catherine is Shuggie's older half-sister and Agnes’ eldest child from her previous. She marries Donald Junior, Big Shug's nephew, and leaves her family behind and to move to South Africa.
Leek
Leek (actual name Alexander) is Shuggie's older half-brother. He is the son of Brendan McGowan and Agnes. Leek sacrifices his opportunity to join art school to stay behind and take care of the family. He feels obligated to nurture Shuggie in a way that prepares him for the real world and its prejudices. He works construction to support Agnes and Shuggie after Big Shug and Catherine leave. When Agnes tries to commit suicide, Leek says he can't handle taking care of everyone anymore and he moves away, severing contact with Agnes.
Lizzie Campbell
Lizzie Campbell is Agnes's mother. She is devoted to her husband Wullie, although she cheats on him while he is away at war. She puts up no resistance when he mysteriously makes the child to whom she gave birth while he was away disappear. She dies within a month of Wullie.
Wullie Campbell
Wullie is Agnes's father. A Catholic, Wullie disapproves of Agnes's marriage to Big Shug, who is Protestant. When Wullie was fighting overseas with the military, his wife Lizzie had an affair with a shop owner so she could secure more food. Upon learning that she had a child while he was away, Wullie took the child away in a pram, returned without the baby, and pretended there had never been a baby when Lizzie asked. Wullie dies of lung cancer.
Bridie Donnelly
Bridie Donnelly is a neighbor of Agnes's in Pithead. Not a drinker herself, Bridie is addicted to Valium pills. She introduces the drug to Agnes, offering to sell it to her at a "special price."
Eugene
Eugene is a cab driver Agnes meets while working at a petrol station. The two begin dating, but Eugene becomes uncomfortable when he learns that Agnes is a recovering alcoholic. After Eugene convinces her to try a sip of wine to prove to herself she isn't as bad as other alcoholics, Agnes relapses. Eugene can't handle Agnes's destructive behavior and abandons the relationship.
Leanne Kelly
Leanne Kelly is a tall blond girl Shuggie becomes friends with. A fellow child of an alcoholic, Leanne is able to relate to Shuggie easily. Although she gets Shuggie to admit he doesn't like girls, and she admits she doesn't like boys, they agree to be boyfriend and girlfriend for the time being. Shuggie stays friends with Leanne when he is a teenager, and the novel ends with the two of them visiting Leanne's alcoholic mother, who lives on the streets.
Brendan McGowan
Brendan McGowan is Agnes's first husband and the father of Catherine and Leek. A devout Catholic, Brendan is faithful to Agnes and his children. When Agnes leaves him for Shug, Brendan tries to convince her to come back to him. He sends support money and has regular visits with his children. When he learns that Catherine considers her surname to be Bain, Brendan abandons Catherine and Leek and no one hears from him again.
