Junie is a twelve-year-old, second-generation Korean American middle school student living in Maryland. Facing severe, racist bullying on her morning bus ride, she struggles with isolation and major depressive disorder. She initially maintains a fatalistic silence about her suffering but gradually learns to navigate her emotional distress. Her journey involves connecting with her heritage through a school oral history project about the Korean War.

Doha is Junie's grandfather, a kind but forceful elder who acts as a crucial mentor to his granddaughter. His past is explored through his experiences as a twelve-year-old boy in Seosan during the outbreak of the Korean War. He provides Junie with necessary cultural context and teaches her about the dangers of remaining silent when witnessing injustice.

Jinjoo is Junie's grandmother, who works as a real estate agent and cares deeply for her family's well-being. Her personal history unfolds through her memories as a ten-year-old girl navigating the North Korean invasion of Incheon. She serves as a symbol of familial responsibility, showcasing the resourcefulness necessary to keep her younger siblings safe during wartime.

Tobias is an eighth-grade student who rides the same bus as Junie. He actively targets her with racist language and slurs, calling her derogatory names based on her Korean heritage. His relentless harassment contributes significantly to Junie's emotional struggles and highlights the pervasive issue of prejudice in her environment.

Patrice is a Black student and one of Junie's closest friends. She is outspoken, proactive, and deeply committed to fighting racism at their middle school. Frustrated by Junie's initial negativity and reluctance to act, Patrice challenges her friends to take a direct stand against discrimination.

Amy is a Jewish middle school student and part of Junie's diverse friend group. Alongside Patrice, she is actively involved in pushing back against the hate speech and vandalism targeting minority students at their school. She provides steady companionship during the group's early activism efforts.

Justin is Junie's older brother, who previously faced his own bullying issues before switching to a different bus and school. He acts as a protective older sibling, regularly checking in on Junie and offering to intervene if anyone hurts her, while encouraging her to confide in him.

Paul is Junie's father and the son of Doha and Jinjoo. He is strict about modern technology, initially refusing to buy Junie a smartphone, but he cares deeply for his children's well-being. He participates in quiet, everyday forms of activism, serving as a model for alternative ways to combat prejudice.

Junie's mother works as a lawyer for the Department of Justice. She is an involved, pragmatic parent who cooks elaborate breakfasts and drives Junie to school when she notices her daughter's distress. She actively seeks professional help for Junie's depression and supports her recovery.

Rachel is Junie's therapist. She provides a safe, objective space for the young girl to discuss her feelings outside of her family dynamic. She equips Junie with coping mechanisms, such as mindfulness and emotional regulation, to help her combat major depressive disorder.

Esther is the only other Korean American student in Junie's grade. She initially distances herself from her heritage and from Junie, attempting to blend in with a different social circle. Over time, she observes the racist incidents at school and deals with her own resulting anxiety.

Dr. Han is Doha's father and a highly respected physician who runs a clinic in Seosan during the 1950s. He acts as a voice of reason amidst the ideological chaos of the Korean War, treating wounded individuals regardless of their political affiliations and speaking out against false accusations.

Gunwoo is one of Doha's closest friends in Seosan. Influenced by his family's suffering under Communist forces, he aggressively supports anti-communist factions. His political radicalization during the war severely strains his relationships and pushes him to make harsh accusations to protect himself.

Sunjin is another of Doha's childhood friends. He lives in the mountains among communist sympathizers, a circumstance born of survival rather than ideology. His vulnerable position places him and his family in constant danger as the war encroaches on their village.

Yuni is Doha's sister. She possesses a strong sense of justice and refuses to stay silent when she witnesses her neighbors making false political accusations. Her bravery in defending innocent people directly exposes her to the brutal realities of military occupation.

Jinjoo's mother comes from a wealthy family and is fiercely devoted to her husband. Accustomed to a comfortable lifestyle, she struggles with the harsh deprivations brought by the North Korean invasion and makes desperate decisions to ensure her husband's safety.

Jinjoo's father is an affectionate parent who spoils his children, occasionally drawing the jealousy of his wife. His connections to a family member in law enforcement put him in grave danger when occupying forces target government workers and their relatives.

Eunjoo is Jinjoo's younger sister. During their perilous journey out of Incheon, she proves frail and fearful, heavily relying on Jinjoo's protection and guidance. She views the occupying forces and foreign soldiers with deep suspicion.

Junsoo is one of Jinjoo's little brothers. Too young to fully comprehend the dangers of the war, he relies entirely on his older sister Jinjoo, who must carry him for much of their difficult journey toward Seoul.

Gomo is Jinjoo's aunt. She suffers immense trauma when soldiers violently target her family due to her son's occupation as a police officer, forcing her to flee to Suwon for survival.

A young domestic worker employed by Jinjoo's family. Faced with starvation and the breakdown of society during the invasion, she prioritizes her own survival over the well-being of the children left in her care.

Stu is a white student at Junie's middle school. He dismisses the concerns of the diverse student body, labeling rumors about hate crimes as fake news and actively antagonizing students who seek to address the school's racist incidents.

Mrs. Medina is Junie's social studies teacher. She assigns a multi-generational interview project that encourages her students to document the experiences of family members who lived through major historical conflicts, sparking Junie's interest in her grandparents' pasts.