Boy is a 20-year-old woman who escapes her abusive father by catching a late-night bus to Flax Hill, Massachusetts. Upon arriving in the unfamiliar town, she seeks stability, taking temporary jobs as a telephone operator and a clerk at an antique bookstore. She approaches relationships defensively, often keeping people at a distance while searching for a place to belong. Her life shifts permanently when she marries a local jewelry maker and becomes a stepmother.

Bird is the bright, observant daughter of Boy and Arturo Whitman, growing up in Flax Hill. An aspiring journalist, she possesses a sharp eye for detail and a direct, matter-of-fact way of speaking. She frequently feels disconnected from her family's quiet dynamics, spending her time mimicking voices and writing letters to investigate her family's history.

Snow is Arturo Whitman's daughter from his first marriage to Julia. She is a beautiful, widely beloved child whom her grandparents and the town revere. Despite the adoration she receives, her presence creates tension in the Whitman household, particularly with Boy. She eventually moves to Boston to live with her aunt and uncle.

Frank is Boy's violent father who works as a rat-catcher on the Lower East Side of Manhattan. He maintains absolute control over his household, subjecting Boy to intense physical and emotional abuse. His preferred method of pest control involves starving rats in his basement before releasing them. His oppressive, terrifying presence drives Boy to flee New York entirely.

Arturo is a former history professor turned local jewelry maker living in Flax Hill. A widower raising his young daughter, Snow, he initially appears aloof and clumsy during his early encounters with Boy. He values craftsmanship over end products and gradually forms a complicated romantic attachment to Boy.

Charlie is Boy's childhood sweetheart from New York, a medical student with a deep devotion to her. He represents a conventional, uncomplicated love that Boy finds both comforting and stifling. He continually reaches out to Boy after she runs away, hoping to rescue her and bring her back to Manhattan.

Veronica, commonly called Webster, is a resident at Mrs. Lennox's boarding house and Boy's first friend in Flax Hill. She is primarily focused on finding a husband and frequently attends dates. Her social connections help introduce Boy to the town's social fabric.

Ted is Arturo Whitman's business partner and Veronica Webster's steady date. He handles the business end of Arturo's jewelry sales. He eventually marries Veronica in a lavish, highly traditional wedding ceremony.

Mia is an aspiring journalist from a wealthy background who rebels against her father's expectations. She meets Boy while working undercover to investigate the secret lives of blonde women. She is fiercely independent, career-driven, and serves as a cynical but loyal confidant to Boy.

Mrs. Fletcher is the blunt, acerbic Englishwoman who owns the local bookstore in Flax Hill. She moved to the town after her American husband's death to feel closer to his memory. She runs a strict shop but provides Boy with a stable job and occasional sharp wisdom.

Sidonie is an intelligent teenager who skips school to read in the local bookstore. She engages in passionate literary debates and is generally charitable in her assumptions about others. Her presence challenges Boy's initial assumptions about the local youth.

Phoebe is a teenager who frequents Mrs. Fletcher's bookstore during school hours. She is highly perceptive and quick to point out prejudices she observes in others, serving as a sharp observer of the racial and social dynamics in Flax Hill.

Kazim is a creative teenager who spends his afternoons drawing comic strips at the bookstore instead of attending school. His artwork often contains allegorical themes about history repeating itself.

Olivia is Arturo's rigid, ambitious mother who wields significant influence over the Whitman family. She is fiercely protective of her family's social standing and makes calculated decisions to maintain their status in Flax Hill. She dotes heavily on Snow but maintains a cold, critical distance from Bird.

Gerald is Arturo's father and the quiet patriarch of the Whitman family. He generally defers to his wife's strong opinions regarding family matters, though he harbors deep-seated fears about societal dangers that occasionally surface during family gatherings.

Agnes is the mother of Arturo's late wife, Julia. She is a close friend of Olivia Whitman but possesses a more easygoing and understanding nature. She remains deeply connected to the Whitman family to stay close to her beloved granddaughter, Snow.

Vivian is Arturo's younger sister, a successful attorney who shares the polished style and mannerisms of her mother, Olivia. Despite her professional achievements, she experiences profound personal setbacks and struggles under the weight of her family's strict expectations.

Clara is Arturo's estranged sister who works as a nurse in Boston. She was sent away from the Whitman family at a young age to live with an aunt. She maintains an independent life away from Flax Hill's expectations and offers a blunt, alternative perspective to her family's choices.

John is Clara's intellectual husband who runs a home school. He spent time in prison during his youth, where he developed a deep appreciation for literature and history. He frequently uses humor to cope with societal absurdities, which sometimes shocks his in-laws.

Louis is Bird Whitman's best friend and steady companion. The son of a jazz pianist and a taxi driver, he is a loyal and supportive presence in Bird's life. He faces local prejudice with initial apathy but is forced to confront it when community tensions rise.