Eugene is an observant, nearly 15-year-old boy adjusting to puberty and his role in a crowded Brooklyn household during the Great Depression. He dreams of becoming a professional baseball player for the Yankees or a writer, keeping a secret journal of his daily observations. Though occasionally selfish and quick to complain about being blamed for household issues, he cares deeply for his family and demonstrates a strong desire to mature.

Kate is the pragmatic and overworked matriarch of the Jerome household. While she does not work outside the home, she bears the immense emotional and logistical burden of managing a crowded, financially strapped house. She harbors deep-seated resentments from her childhood but remains fiercely dedicated to keeping her family intact and properly fed.

Jack is the weary but resolute patriarch of the family, working grueling hours as a garment worker and a party favor salesman to support seven people. He takes his role as a provider and moral guide incredibly seriously, insisting on principled behavior. Despite physical exhaustion and health scares, his devotion to his family and his Jewish heritage never wavers.

Blanche is Kate's widowed younger sister who moved into the Jerome household with her two daughters after her husband's death. She suffers from asthma and failing eyesight, making it difficult for her to find steady work. Temporarily paralyzed by grief and indecision, she struggles to parent effectively but eventually strives to reclaim her independence and stop relying on her sister's charity.

Stanley is Eugene’s older brother, who entered the workforce immediately after high school to help support the family. He feels the heavy pressure of his responsibilities and strives to live by his father's strict moral code, though his youth sometimes leads him into trouble. He is highly protective of Eugene and fiercely advocates for his younger brother's future success.

Nora is Blanche’s headstrong, ambitious eldest daughter. She is an avid dancer who desperately wants to secure a Broadway role to gain financial independence for herself and her immediate family. Frustrated by her mother's indecisiveness and the loss of her father, Nora frequently rebels as she tries to establish agency over her own life.

Laurie is Blanche’s youngest daughter. She was born with a heart flutter and is subsequently treated with extreme delicacy by her mother and aunt. Studious and quiet, she spends much of her time reading, though her cousins suspect she occasionally uses her condition to avoid chores.

Dave is Blanche's deceased husband and father to Nora and Laurie. He died of cancer six years prior to the events of the story. His absence leaves a profound emotional void in his family's lives, shaping their current financial struggles and emotional insecurities.

Frank is an Irish neighbor living across the street from the Jeromes. He briefly serves as a potential suitor for Blanche before a car accident prevents their date, sending him to upstate New York for rehabilitation.

Andrew is a coworker of Stanley's at the hat factory. When he accidentally spills oil on some inventory, his employer attempts to dock his pay, prompting Stanley to intervene on his behalf.

Mr. Stroheim is Stanley's demanding boss at the hat factory. He runs a strict workplace and demands an apology letter from Stanley after an altercation over another employee's mistake.

Sholem is Jack's cousin from Poland. As tensions rise in Europe, he successfully escapes with his family and heads to New York, prompting the Jeromes to prepare to take them in.

Michael is Jack's deceased older brother. He died fighting in World War I, and his memory deeply influences Jack's perspective on the impending global conflict and his sons' brotherhood.