Michael is a 12-year-old Cuban immigrant living in the Bronx who pitches for the Clippers Little League team. He possesses a remarkably fast throwing arm, capable of hitting speeds that intimidate older players. Following his father's sudden death, Michael lives in constant fear that the state will discover his situation and place him in foster care. He finds his only true peace on the pitcher's mound.

Manny serves as the Clippers' catcher and operates as Michael's most trusted confidant. He is highly observant and constantly talks, using his sense of humor to deflect unwanted attention from adults. He actively schemes to protect Michael's secret living situation from nosy officials.

Carlos is Michael's 17-year-old brother who suddenly finds himself acting as the head of the household. He abandons his own teenage years to work multiple jobs, including shifts at Hector's Cafe, to keep a roof over his brother's head. The intense pressure of managing bills and evading Family Court causes him significant stress.

Mrs. Cora lives in the same Bronx apartment building as the Arroyo brothers. She acts as their adopted grandmother and is one of the few adults fully aware of their father's death. She frequently cooks for Michael, providing a safe haven when the stress of his hidden life becomes overwhelming.

Mr. Minaya manages the Clippers and acts as a protective presence for his players. He strictly enforces a rule against trash talk and attempts to shield his team from the aggressive politics of rival coaches. He suspects something is amiss in Michael's home life but prioritizes keeping the boy involved in baseball.

Ellie is a talented athlete with a surprisingly strong throwing arm who frequents the baseball fields near Yankee Stadium. She shares Michael's Caribbean roots and bonds with him over a childhood song about a cat. She maintains strict boundaries about her personal life, which creates friction as Michael tries to learn more about her.

Mr. Gibbs balances his role as a Little League coach with his career at the Administration for Children's Services. He notices the continuous absence of Michael's father and begins to investigate the family's living situation. His genuine desire to help vulnerable children inadvertently threatens the Arroyo brothers' independence.

El Grande is a famous Cuban immigrant who pitches for the New York Yankees. He stands as an aspirational figure for the neighborhood children, particularly Michael, who closely monitors his games from a fire escape. His success represents the ultimate fulfillment of the American Dream for the local baseball community.

Papi is the late father of Carlos and Michael, a former Cuban shortstop who worked as a gypsy cab driver in New York. He suffered a fatal heart attack after defending a passenger, leaving his sons to fend for themselves. He instructed his boys to avoid police contact and stay together at all costs.

Uncle Timo is a young actor who favors casual American slang. He agrees to help his nephew Manny by using his theatrical skills to impersonate a specific figure, hoping to satisfy the inquiries of child services and protect the Arroyo brothers.

Ramon is a sixteen-year-old resident of the South Bronx who avoids legitimate work in favor of petty theft. His actions occasionally intersect with the Arroyo brothers, pulling them closer to the police attention they desperately want to avoid.

Justin pitches for the Westchester South Little League team. He possesses an aggressive demeanor and grows intensely jealous of Michael's superior athletic skills. He frequently resorts to throwing wild pitches and shouting at umpires when the game turns against him.

Justin's father coaches a rival Little League team and refuses to accept that a twelve-year-old can naturally pitch as fast as Michael. He organizes a formal complaint with league officials, demanding documentation to prove Michael's age and actively working to get the boy disqualified.

Mr. Lima works in public relations for the Bronx borough president. He persistently tracks Michael down to arrange a public award ceremony, completely unaware that his official presence terrifies the young boy.

Kelvin is a player for the Clippers who admires Michael's pitching speed. He contributes to the team's dynamic and relies on Michael's skills to secure victories against rival neighborhoods.