Jeffrey is an eleven-year-old orphan who runs away from his emotionally distant aunt and uncle. Unaware of the strict racial segregation in Two Mills, he casually crosses boundaries and interacts with everyone he meets. He possesses incredible athletic abilities and a deep desire to find a genuine home and family.

Amanda is a twelve-year-old Black girl living in the East End of Two Mills. She is fiercely protective of her book collection, carrying it to school daily to keep it safe from her younger, destructive siblings. She is assertive, kindhearted, and quick to defend those she cares about.

Grayson is an elderly white park attendant working in the West End of Two Mills. A former minor league baseball pitcher, he lives a quiet, solitary life. He steps in to care for Jeffrey, providing him with food, clothes, and a safe place to sleep in the baseball equipment room.

Mars Bar is a twelve-year-old Black boy who serves as a primary bully in the East End. Known for constantly eating the candy that gives him his nickname, he projects a tough exterior and actively dislikes outsiders crossing into his neighborhood.

John is a twelve-year-old, unusually large Little League pitcher who leads a gang called the Cobras. He dominates the local baseball field with his fastball and aggressively protects his turf in the West End from anyone he perceives as an outsider.

Mrs. Beale is the warm and caring matriarch of the Beale family in the East End. She provides structure, clean clothes, and a loving environment, treating houseguests with the same affection and discipline she shows her own children.

Mr. Beale is Amanda's father. He is perceptive and compassionate, quickly realizing that Jeffrey has no actual home to return to and fully supporting the decision to let the boy stay with their family.

Hester is one of Amanda's two younger siblings. Energetic and easily entertained, she quickly bonds with visitors who are willing to read to her and play with her.

Lester is Amanda's younger brother. Much like his sister Hester, he is rambunctious and instantly takes a liking to anyone who joins in their household games.

Russell is John McNab's eight-year-old younger brother. Growing up in a chaotic household in the West End, he is rowdy, prone to running away, and easily influenced by dares and bribes.

Piper is John McNab's other eight-year-old brother. He mirrors Russell in his rebellious behavior, using school attendance as a bargaining chip to witness increasingly dangerous stunts.

George is the neglectful father of John, Russell, and Piper. He struggles with alcohol addiction and actively teaches his sons prejudiced, hostile attitudes toward the residents of the East End.

Mrs. Pickwell is a matriarch in the West End who constantly feeds a table full of ten children, extended relatives, and down-on-their-luck strangers. She establishes a welcoming, structured environment for anyone who needs a meal.

Hands is an older, skilled football player who enjoys testing out athletic abilities. He is friendly toward newcomers who can hold their own on the field.

Mr. Cobble owns a pizza shop featuring a legendary, volleyball-sized knot. He uses the knot as a promotional challenge for the town's children, promising free pizza for a year to the winner.

Finsterwald is an unseen recluse whose yard is the subject of intense local superstition. Children believe that setting foot on his property results in permanent disappearance or a lifetime curse.