A charismatic and confident 12-year-old growing up in the West End of Louisville, Kentucky. Though he struggles in school with reading, he is fiercely determined and constantly shadowboxes around his neighborhood. He deeply resents the racism that segregates his city. He channels his physical energy into dreams of becoming a rich, famous boxer who can provide for his family.

Cassius's younger brother by two years. The two siblings share a bedroom, household chores, and street games. Rudy frequently rides on the handlebars of Cassius's bicycle and shares in his sibling's dreams, though he approaches the world with slightly more caution.

Cassius's best friend and the narrator of the story's prose sections. He excels academically in spelling and reading, contrasting heavily with Cassius's struggles in the classroom. He attends a Catholic school but spends his free time supporting his friend's athletic aspirations.

Cassius and Rudy's mother. She works hard cleaning houses for wealthy families and takes deep pride in her labor. A devoutly religious woman who sings at Mount Zion Baptist Church, she serves as her son's primary emotional support.

The towering, emotive father of Cassius and Rudy. A talented artist who makes his living painting commercial signs and billboards around Louisville. He harbors frustration over the racial barriers that prevented him from achieving greater artistic fame.

Cassius's grandfather. He is a former baseball player who was barred from the major leagues due to segregation. He imparts vital family history, card tricks, and moral lessons to his grandsons.

A local police officer who also runs the boxing program at the Columbia Gym. He meets Cassius during a moment of intense anger over a stolen bicycle. He offers the boy a constructive outlet and becomes a strict but encouraging mentor.

The biggest, strongest kid in Cassius's neighborhood. He bullies the local children and demands tolls to walk down certain streets. He stands as a major physical obstacle for the local kids.

A neighborhood girl who has an obvious crush on Cassius. She is observant and sometimes challenges him on his emotionally distant behavior. She gifts him a rabbit's foot keychain for good luck.

One of Cassius's core group of neighborhood friends. He frequently joins in on bets and watches televised boxing matches with the group. He develops a romantic interest in Teenie as the boys grow older.

An athletic kid in the neighborhood whose life is permanently altered by a tragic gas drain explosion during a baseball game. His severe injuries force him into home tutoring and limit his physical interactions.