Charley is a 12-year-old girl living in the Jim Crow South who dreams of becoming the first Black female pitcher in professional baseball. She is passionate, competitive, and highly determined, actively resisting the traditional gender roles pushed upon her by her mother. She spends her summer days practicing baseball with her friends and listening to her grandfather's stories about their family's history.

Nana Kofi is Charley's beloved grandfather and the patriarch of the family. A survivor of enslavement and a veteran of the Civil War, he imparts wisdom and generational history to Charley through his vivid stories. Despite struggling with a frail cough and declining health, he remains a strong, calm, and protective mentor who encourages Charley's baseball dreams and resilience.

Willie is Charley's 12-year-old best friend who shares her birthday and her love for baseball. Humorous and loyal, Willie dreams of becoming a musician like his father, though he spends most of his time trying to hit Charley's fast pitches. He provides a supportive and lighthearted presence in Charley's life, though their friendship faces tests from outside bullies and the pressures of their segregated town.

Cecil the Third is a local bully and the pastor's son. He is known for playing mean pranks and viewing himself as superior to others, particularly regarding his baseball skills. Sexist and highly competitive, he routinely taunts Charley for being a girl and challenges her team to a high-stakes bet at the upcoming church picnic.

Momma is Charley's strict but loving mother. She is a firm believer in traditional gender roles and expects Charley to pursue elegant, feminine activities like playing the flute and sewing rather than baseball. She is deeply protective of her family and an excellent cook who hosts large Sunday dinners for the community.

Daddy is Charley's emotionally supportive father who works away from home as an oyster fisherman in Baltimore. Having once tried out for a minor league baseball team, he actively encourages Charley's athletic talent and shares her passion for the game. His periodic visits home are a source of great joy for Charley.

Henry, affectionately nicknamed "Socks," is a shy but friendly white boy whose family owns the local general store. He frequently plays outfield with Charley and Willie, sharing their love for the game but remaining somewhat sheltered from the harsh realities of the racial segregation that restricts his friends.

Uncle Albert is Charley's highly intelligent and successful uncle. Working as a railroad engineer, he stands out as a symbol of Black achievement in their community during a time of intense racial prejudice. He frequently uses his prized Model T car to take his nieces and nephews on rides.

Johnnie is Willie's older brother who is preparing to get married to his fiancé, Ruth. He acts as a reluctant chaperone for the younger kids when they need adult supervision, helping them navigate the strict and often dangerous rules of their segregated town.

Based on the real-life historical figure, Mrs. Mary Bethune is a well-dressed, eloquent human rights activist and educator. She visits the church to advocate for Black women's equality and education, deeply inspiring Charley with her encouragement to follow her dreams and her validation of women in sports.

Berry is Charley's ten-year-old niece, one of a set of triplets. Though her parents do not want her playing baseball, she eagerly supports Charley's team and steps up to volunteer as catcher when they are outnumbered during the big game.

Plum is Charley's young nephew, part of a set of ten-year-old triplets. Despite being uncoordinated and lacking baseball experience, he enthusiastically tries to follow Charley's written instructions to help her win the high-stakes bet against Cecil.

Juju is Charley's nephew and one of the ten-year-old triplets. Like his brother Plum, he struggles with the athletic demands of baseball but remains a dedicated, albeit unskilled, member of the newly formed Black Stars team.

Paul is a confrontational white boy who roams the town with his friends and dog. He uses his racial privilege to harass Black residents, instigating conflicts with Nana Kofi and later challenging Charley and Willie over their presence at a segregated baseball park.

Uncle Rinney is a local Black business owner who operates a grocery store and secretly hosts United Negro Improvement Association (UNIA) meetings. He provides a safe community space for Black men to discuss freedom, activism, and equal rights.

Gwen is Charley's older sister. She supports Charley's dreams and surprises her with a cherished gift: a baseball glove signed by L.G., a professional Black female player from the North.

Cousin Kofi is Nana Kofi's relative who shares his name. He features prominently in Nana's memories as a brave companion who endured the horrors of enslavement, survived a shipwreck, and eventually fought alongside him in the Civil War Navy.