Joey is a bright, highly articulate 12-year-old Jewish boy living in Brooklyn during the late 1930s. Following his parents' divorce and his relocation to a largely Gentile neighborhood, he suffers frequent physical abuse from local anti-Semitic bullies. Resourceful and deeply in need of a father figure, he possesses an encyclopedic knowledge of baseball and politics, prolifically writing letters to public figures to solicit military action and personal favors.

Charlie is a professional baseball player hailing from Racine, Wisconsin. He maintains a gruff, curmudgeonly exterior and holds conservative Midwestern political views that clash with his new Brooklyn acquaintances. Despite initially rejecting Joey's dramatic letters, Charlie possesses a strong moral compass that forces him to intervene when he learns the boy faces genuine abuse.

Hazel is a popular torch singer who performs in trendy New York supper clubs. Sophisticated and generous, she operates in high-profile entertainment circles while remaining thoroughly grounded. She easily embraces Joey, treating him to outings and inviting him onto stage to sing duets with her.

Ida is Joey's witty and resilient mother. Following a difficult divorce where her husband abandoned the family for a socialite, she relocates with her sister to a non-Jewish Brooklyn neighborhood. Rather than succumbing to bitterness, she focuses her energy on community charity and loving her son.

Carrie is Joey's aunt who shares their Brooklyn apartment. She practices traditional Judaism and holds strong opinions about the people influencing Joey's life. Initially skeptical of the Gentile baseball player entering their world, she warms to his presence and bakes for him regularly.

Dr. Weston is a psychologist who evaluates Joey after an incident of vandalism. He becomes the boy's regular therapist, listening patiently as Joey details his neighborhood struggles, elaborate schemes, and developing connection with Charlie Banks.

A devout and traditional Jewish leader charged with overseeing Joey's transition to manhood. Reserved and principled, he initially balks at the idea of bending religious rules but proves capable of unexpected flexibility when presented with Joey's unique family situation.

David is Joey's biological father who leaves his family to marry a Manhattan socialite. He completely withdraws from his son's life, ignoring phone calls and refusing to attend important milestones. His emotional and physical absence serves as the primary catalyst for Joey's persistent search for a surrogate parent.

Craig is Joey's best friend and upstairs neighbor, affectionately known as "The Shadow." A young Japanese-American boy, he shares Joey's quick wit, democratic worldview, and entrepreneurial spirit. He frequently experiences the same neighborhood bigotry and bullying as Joey.

Stuke is the first baseman for the New York Giants. He serves as a supportive presence in the locker room and acts as Charlie's closest confidant, eventually extending his friendship to young Joey as well.

Rachel is a beautiful young girl in Joey's class at Alexander Hamilton Junior High School. She is the target of Joey's immature attempts at securing attention before he eventually transitions to writing her heartfelt letters under Charlie's guidance.

Lenny is a vicious neighborhood bully steeped in anti-Semitism. He regularly attacks Joey and Craig, leaving Joey with bruises that the boy attempts to hide from his family.

Mrs. Hicks is Joey's long-suffering junior high school teacher. She frequently writes exasperated report card notes to Ida Margolis regarding Joey's rebellious behavior and creative interpretations of history, though she acknowledges his exceptional intelligence.

Stephen Early is the White House Press Secretary under President Roosevelt. He patiently answers Joey's letters, respectfully debating the boy's dramatic warnings about global military strategy and foreign invasions.

The President of the United States. He receives regular letters from Joey offering campaign dollars, polling analysis, and unsolicited advice on international affairs.

The First Lady of the United States. She sponsors a national essay contest that captures Joey's attention, prompting him to write passionately about his personal heroes.

Nana Bert is David Margolis's new wife, a Manhattan socialite. She actively prevents Joey from speaking to his father by refusing to put his phone calls through to him.