Park is a half-Korean high school student who prefers to keep his head down, listen to alternative music, and read comic books. He lives in a stable, middle-class home with his parents and younger brother. Though he tries to avoid drawing attention to himself to escape mild bullying, his routine breaks when he offers his bus seat to the new girl.

Eleanor is a new student who stands out due to her bright red hair and tendency to wear baggy men's clothing. She recently moved back into a deeply unstable and abusive household. Intelligent and heavily guarded, she dreads both the relentless bullying at school and the oppressive fear at home until she begins a quiet friendship on the bus.

Richie is Eleanor’s volatile and abusive stepfather. He controls the household through fear and physical intimidation, forcing his wife and stepchildren to constantly monitor his moods. He drinks heavily and dominates the family's meager resources.

Sabrina is Eleanor's mother, a woman trapped in an abusive marriage with Richie. She attempts to keep the peace and protect her children, but she is frequently the target of her husband's rage. She relies on small routines to maintain brief moments of normalcy.

Park's father is a tall, level-headed man who encourages Park's involvement in taekwondo. He provides a stable and loving environment for his family, standing in contrast to the chaos of Eleanor's home. He occasionally clashes with Park over traditional masculine expectations.

Mindy is Park's mother, a highly successful and popular local hairstylist. She takes pride in appearances and initially disapproves of Eleanor's tomboyish, unconventional style. She worries about her son's social standing but possesses a caring nature beneath her superficial concerns.

Josh is Park’s younger brother. Despite being younger, he is physically larger than Park and comfortably fits into the traditional masculine expectations of their father. He occasionally teases Park about his daily life.

Tina is a popular girl at school who acts as one of Eleanor's primary bullies, frequently hurling insults at her. She has a brief romantic history with Park from middle school, which complicates the social dynamics and shifting loyalties on the bus.

Steve is a neighborhood bully and one of Park's peers. He relentlessly harasses Eleanor on the school bus and frequently targets Park, utilizing racial slurs and aggressive taunts until Park decides to stand his ground.

Cal is Park’s friend at school. He frequently pesters Park about his relationship status, attempts to set Park up with other girls, and acts as a sounding board for teenage gossip.

Ben is one of Eleanor’s younger brothers. He shares a cramped bedroom with Eleanor and their other siblings, enduring the oppressive atmosphere of Richie's house while seeking small moments of connection with his older sister.

Maisie is Eleanor’s younger sister. She shares the tiny bedroom with the rest of the siblings and occasionally barters with Eleanor, offering to keep secrets in exchange for using Eleanor's makeup or reading her comic books.

Mouse is another of Eleanor's younger sisters. She struggles to learn childhood games and shares the crowded bedroom with her siblings, staying as quiet as possible to avoid drawing Richie's attention.

Eleanor’s biological father is an absentee parent who occasionally sees his children but generally avoids responsibility. He drinks heavily, speeds while driving, and prioritizes his new fiancée over his children's well-being.

DeNice is a friendly classmate who reaches out to comfort Eleanor after a harsh bullying incident. She and her friend Beebi offer Eleanor a safe place to sit at lunch, providing a rare moment of schoolway kindness.

Beebi is a classmate who, along with DeNice, becomes one of Eleanor's few friendly acquaintances at school. She actively includes Eleanor in their social circle during lunch and gym class.

Mr. Stressman is the high school English teacher who encourages his students to memorize poetry. He is highly impressed by Eleanor's recitation of Maya Angelou's "Caged Bird," rewarding her with a hug and validating her academic abilities.

Park's grandmother lives next door to his family. She frequently hosts the family for traditional dinners and holds long conversations over the phone, occasionally gossiping about neighborhood matters.