Steve is an eight-year-old Jewish boy living in Brooklyn in 1948 whose entire world revolves around the Brooklyn Dodgers. He struggles significantly with impulsivity and keeping his temper in check, often acting without thinking. When his idol moves into his neighborhood, Steve learns valuable lessons about self-control, friendship, and the importance of standing up against discrimination. His interactions with his new neighbors challenge him to channel his frustration constructively rather than through physical outbursts.

Jackie is a star first baseman for the Brooklyn Dodgers who faces immense public pressure and systemic racism. Despite his fame and the historic nature of his career, he is a grounded, friendly man who values his family and community. He expertly balances his role as a public pioneer with his private identity as a husband and father. He takes an active interest in his young neighbor, modeling the dignity and restraint required to face prejudice without resorting to violence.

Archie is a principled family man who provides his son with a firm ethical framework. He draws direct parallels between the antisemitism his parents fled in Russia and the racism Black Americans face, using history to teach his son about justice. He bonds with his son over baseball broadcasts and the meticulous construction of a model airplane, hoping to instill patience and discipline. Though sometimes stern, his actions are consistently motivated by deep paternal love.

Sarah is a compassionate and practical woman who puts her family's values into action through everyday deeds. She firmly opposes the neighborhood's prejudice, declaring that her family's Jewish heritage demands they stand against discrimination. She is socially adept and emotionally intelligent, successfully bridging the gap between her son's hero-worship and a genuine friendship with their new neighbors.

Rachel is an elegant, intelligent woman who provides a stable and loving center for her family amidst the pressures of public scrutiny. She worked as a riveter on airplanes during World War II and brings quiet strength to her household. She is a gracious neighbor who helps facilitate the friendship between her husband and the local children, always acting with sensitivity and warmth.

Sena is a typical Brooklyn child and a loyal companion in everyday activities like stickball and sledding. As a New York Yankees fan, she provides a playful counterpoint to the intense Dodgers obsession found in her neighborhood. She serves as a pragmatic voice of reason, often urging caution when situations threaten to escalate.

Jackie Junior is a young boy who moves to Brooklyn with his famous father and supportive mother. He participates in family activities and helps integrate his family into the local community by making paper decorations and playing with the neighborhood children.

Miss Maliken is a schoolteacher who becomes the target of childhood impulsivity. After enduring a series of pranks, she is pushed into a hedge outside the school, an event that triggers serious disciplinary action for her students.

Mrs. Palin is a Black woman who purchases the house at 5224 Tilden Avenue, defying a discriminatory neighborhood petition aimed at blocking the sale. She rents the top floor of her duplex to a famous athlete, setting the neighborhood's integration in motion.

Roy Campanella is a catcher for the Brooklyn Dodgers. He participates in welcoming young fans outside the stadium, graciously signing autographs and representing the integrated future of baseball.

Bubbe is an older family matriarch who attends the extended family's Hanukkah celebration. She demonstrates generational acceptance by warmly and immediately embracing the new neighbors when they arrive to share in the festivities.