Kimberley is a brilliant, driven student who recently immigrated to the United States. She leads an exhausting double life, attending public school during the day while working long hours in a Chinatown sweatshop at night. Resourceful and mature for her age, she serves as her mother's interpreter while experiencing severe poverty.

Ma is a gentle, hardworking former music teacher from Hong Kong. She holds firmly to traditional Chinese values and Buddhism while working six days a week in a factory. Widowed when Kimberley was young, she sacrifices her own comfort to provide her daughter with an education.

Aunt Paula is a calculating, proud businesswoman who co-owns a Chinatown sweatshop. Though she facilitates her sister's immigration, she houses Ma in extreme poverty and demands repayment through grueling labor. She frequently measures her own son's accomplishments against Kimberley's academic successes.

Matt is a young Chinese immigrant who works alongside Kimberley in the sweatshop. Pragmatic and deeply responsible for his family, he takes on extra labor in Chinatown to support them. He understands the realities of immigrant poverty that Kimberley's school friends cannot grasp.

Annette is Kimberley's first real friend in America. Coming from a comfortable household in Brooklyn, she pursues passionate interests in social causes and theater. Well-meaning and generous, she struggles to comprehend the depths of Kimberley's poverty.

Curt is a wealthy, artistic student at Harrison Prep who befriends Kimberley. Protected by his family's trust fund, he takes a casual approach to academics and is often oblivious to his own privilege. He frequently reminds Kimberley of the drastic financial differences between their worlds.

Uncle Bob is an American-born Chinese businessman and Aunt Paula's husband. He co-owns the sweatshop that employs his sister-in-law. Although he steps back from daily operations due to health issues, he remains a figure of authority in the family.

Nelson is Aunt Paula's son and Kimberley's cousin. Raised in relative comfort, he attends a private school and is heavily favored by his mother. He often acts as the benchmark used to measure Kimberley's achievements.

Mrs. Avery is Annette's mother and a local real estate agent. She provides a welcoming home environment for her daughter's friends, living in a clean Brooklyn neighborhood that contrasts sharply with Kimberley's conditions.

Mr. Bogart is Kimberley's elementary school teacher. He is harsh and impatient, giving Kimberley a zero when she attempts to look at a neighbor's paper to understand a confusing assignment.

Mrs. LaGuardia is the principal of Kimberley's public elementary school. She recognizes Kimberley's academic potential despite her language barriers.

Dr. Weston is an administrator at Harrison Prep. Impressed by Kimberley's mathematical abilities during her interview, he becomes a supportive figure.

Luke is a bully at Kimberley's public elementary school. He repeatedly picks fights with her until she realizes his aggression masks a boyhood crush.

Greg is a student at Harrison Prep who attempts to bully Kimberley over her handmade clothing.

Tammy is a popular girl at Harrison Prep. Her friendly overtures toward Kimberley are complicated when a dropped cheat sheet leads to Kimberley being unfairly accused of academic dishonesty.

Mrs. Reynolds is a science teacher at Harrison Prep who initially suspects Kimberley of cheating but ultimately gives her the benefit of the doubt.

Dr. Copeland is the head of the math and science department at Harrison Prep. Initially skeptical of Kimberley's abilities, he subjects her to an oral exam but is eventually won over.

Mrs. Wu is Matt and Park's mother. She works in the Chinatown factory and struggles with a heart condition, relying heavily on Matt.

Park is Matt's younger brother. He has a developmental disability that carries a quiet stigma within the Chinese immigrant community.

Vivian is a friendly girl in the Chinatown community. She begins dating Matt during their high school years, representing a traditional path.

Mr. Al is the owner of a used furniture store in Kimberley's rundown Brooklyn neighborhood. He eventually informs the Changs that the area is scheduled for demolition.

Kerry is a senior at Harrison Prep who works as an English tutor. To Kimberley's surprise, Kerry is also a scholarship student, which helps put Kimberley at ease during their sessions.