Maggie Johnson - We first meet Maggie as a small slight girl who suffers from the violence of her family.  She grows up to be a beautiful but timid young woman in the slum and she takes a sewing job in a sweatshop.  She becomes enamored of her brother's friend Pete who takes her to dance halls and plays.  When her mother denounces her in a drunken rage she leaves her family's apartment to be with Pete.  When Pete rejects her she tries to return home but is rebuked by her mother and brother.  Maggie becomes a prostitute and eventually drowns herself in the East River.

Jimmie Johnson -- At the beginning of the story Jimmie is a small Bowery urchin who picks fights with both friends and foes.  Like his sister Maggie, Jimmie suffers from the violence of his mother and father and grows up to be an equally violent young man.  He works as a truck driver, which affords him plenty opportunities to engage in street fights.  The only thing he fears and respects are fire engines because they have the power to destroy his cab.  Jimmie gets drunk often, amasses an extensive record with the police and uses and abandons women.  He is friends with Pete but fights him after Pete has taken Maggie.  Although he briefly entertains thoughts that rationalize Maggie's behavior he rejects her when she tries return home.

Tommie Johnson - Tommie is Jimmie and Maggie's baby brother.  He dies while still a toddler and Maggie steals a flower for his coffin.

Mary Johnson- Mary is Jimmie and Maggie's mother.  She epitomizes both the animalistic determinism and the hypocritical morality of the slums.  She is a drunkard and vacillates between violent outrage and mournful emotional displays.  Although she beats and insults her children and regularly runs afoul of the law she assumes the moral virtue to judge her daughter guilty of sin for having taken up with Pete.  She denounces Maggie as a fallen woman and refuses allow her to return home after Pete rejects her.  Upon learning of Maggie's death she melodramatically and loudly mourns for her daughter and at the urging of her neighbors forgives her. 

Mr. Johnson (The Father) - Mr. Johnson is consumed by self-pity and hatred of his wife.  He does not hesitate to brawl loudly with his wife and attract the neighbor's attention but he beats his son for fighting and upbraids him for striking his sister in public.  He drinks himself to death before Maggie and Jimmie grow up.

Pete - Pete is Jimmie's older friend who comes to his aid when Jimmie is a young street urchin fighting a rival gang.  When Jimmie is a young man Pete comes to the family's apartment and Maggie becomes enamored of him.  He takes Maggie to plays and music halls and eventually offers to take the girl home with him when her mother denounces her.  Pete takes up with Nell, however, and rejects Maggie because her family has repudiated her and he fears loss of social status by being associated with her.  He becomes a pitiful drunk who spends his money impressing prostitutes who have nothing but contempt for him.

Nell - Described as a "woman of brilliance and audacity", Nell is a professional prostitute who lures Pete away from Maggie in order to use him for money.

The Beggar Woman - The old woman lives on the floor below the Johnson's apartment and offers shelter to Jimmie when he is a child and Maggie when her family has rejected her.

Mrs. Smith - a stereotyped neighbor with missionary zeal, she leads the neighbors in convincing Mary to forgive her dead daughter so that her sins can be judged in heaven.