Connell Waldron
Connell is a quiet, working-class boy. He is affable and popular in high school, where he is known for his good looks and athletic ability. His desire to be liked and avoid unwanted attention causes him to reject Marianne in public, even as he falls in love with her in private. With Marianne's encouragement, he attends the prestigious Trinity College in Dublin. There, he finds that the attributes that made him popular in high school cause people in college to look down on him. His working-class background causes him to feel alienated from his peers and conflicted about his upward mobility. During college, he discovers a passion and talent for writing. He is eventually accepted into a prestigious creative writing graduate program. He later feels that his moral, intellectual, and creative development were entirely spurred by Marianne.
Marianne Sheridan
Marianne is a young woman and a schoolmate of Connell's. She is an outcast in high school because of her strong opinions, her unwillingness to aspire to popularity, and her unconventional self-presentation. She is from a notably wealthy family, and initially develops a relationship with Connell because her family has hired Connell's mother to clean their house. In college at Trinity, Marianne becomes an object of admiration. She also excels academically in her study of politics and history. However, she continues to feel haunted by her past. Marianne's family members, especially her older brother, are physically and emotionally abusive. Even when living far from home, she develops self-destructive behaviors. She develops a severe eating disorder, and asks men to behave violently towards her. Despite these personal problems, Marianne is a deeply rational and intelligent person with an analytical outlook.
Lorraine
Lorraine is Connell's mother. She works as a cleaner for Marianne's family, and this connection is the occasion for Marianne and Connell to develop a personal relationship. She is relatively young, having had Connell as a teenager, and her relationship with her son is marked by honesty and openness. Her occasional sharpness with Connell—especially when she disapproves of his behavior towards Marianne—belies her deep love for him. She also feels maternal and protective towards Marianne, and offers her a parental care that her own family cannot.
Alan
Alan is Marianne's older brother. He is deeply insecure and obsessed with being liked. The book's greatest antagonist, Alan is extremely sadistic towards Marianne. He mocks her for being friendless, forces her into confrontations, and physically hurts her. His abuse is at the root of most of Marianne's problems, and it continues to mount in intensity and cruelty, becoming so frightening that Connell is forced to intervene.
Jamie
Jamie is Marianne's boyfriend for a period after she and Connell have broken up. He is widely disliked and is considered pretentious, unintelligent, and spoiled. He enjoys frightening and humiliating Marianne, and is eager to comply when she asks him to act violently during sex, never bothering to learn about the trauma behind her request. He is part of a campus debate society that invites a neo-Nazi to speak, and expresses political views that disparage everyone from Asian people to drug addicts. Rooney suggests that these attitudes are rooted less in ideological conviction than in complete self-absorption and egotism. Marianne remains with him primarily because she enjoys his transparent motives and simplicity. When she grows tired of these, she stays with him out of fear that he and her friend Peggy will react badly. When she does break up with him, he tells their social group about her specific desires to be dominated, causing her friends to abandon her.
Peggy
Peggy is one of Marianne's friends from university. The two are initially close, but have a falling-out when Marianne ends a destructive romantic relationship with her boyfriend Jamie. Peggy is shallow and controlling, cloaking these tendencies as independence or political iconoclasm. She often uses the language of feminism and moral authority to defend the status quo or make Marianne feel guilty. Peggy dislikes Connell, and often acts scornful of his class and cultural background. After their friendship ends, Marianne realizes that she did not like Peggy as a person, but rather tolerated her because she felt flattered by Peggy's attention.
Joanna
Joanna is Marianne's other close friend from Trinity. She is, in a sense, Peggy's opposite: she is deeply practical and honest, with little interest in pretension or social status. Joanna stays loyal to Marianne through the ups and downs of her social life in college, remaining close to her even when her other friends have abandoned her. Ambitious and hardworking, Joanna has none of Marianne's reservations about life in the corporate world. This attitude helps Marianne relax, giving her a model for prioritizing self-preservation and survival.
Denise
Denise is Marianne's own mother, and is in many ways the opposite of Connell's mother Lorraine: cruel, manipulative, and protective of the strong over the weak. She ignores, or even encourages, the abusive behavior of Marianne's brother. She herself generally ignores her daughter, paying attention to her primarily to express disdain or create anxiety. Wealthy and materialistic, Denise is seen as somewhat strange by her wider community as well.
Helen Brophy
Helen is Connell's girlfriend during college. He enjoys being in a relationship with her, not because the two share a particularly close connection, but because she represents a fantasy of normalcy and healthiness that Connell finds soothing. Helen is sociable, unintimidating, and traditionally feminine. She is also very conventionally attractive. She tries to become close with Marianne to avoid tension with her, but is unable to tolerate Marianne's personality, especially her scorn for small talk. She becomes jealous of Marianne, suspecting (correctly) that Connell still has feelings for her.
Niall
Niall is Connell's close friend and roommate in college. He shares some of Connell's bewilderment in the face of Trinity's social norms, and is quietly supportive of Connell, even helping him seek help for his mental health. Though never a major character, Niall is a regular presence in the novel, accompanying Connell on his travels through Europe.
Rachel Moran
Rachel is the most popular girl in Connell and Marianne's high school grade. She has a crush on Connell, though she is interested in him primarily as a badge of popularity rather than as an individual. She also bullies Marianne. Connell asks her, not Marianne, to be his date for a major high school dance, igniting Connell and Marianne's first breakup.
