Jurgis Rudkus The protagonist. He is a Lithuanian immigrant who believes in himself and his work ethic but finds that making a living for his wife and family takes more than hard work and dedication. He believes in the American dream and wants to make it a reality, but in the end, he discovers that he was following the wrong dream.
Ona Lukoszaite Jurgis' fiancée and later his wife. Her frail nature — both physically and emotionally — does not lend itself towards survival in the Packingtown jungle in which she must attempt to live.
Elzbieta Lukoszaite (Teta Elzbieta) Ona's stepmother. She endures one tragedy after another, never really living, only surviving.
Marija Berczynskas Ona's cousin. Although the prototype of strength and endurance for most of the novel, she too is eventually defeated by the capitalistic system, although she is matter-of-fact about her fate.
Jonas Elzbieta's brother. He comes to America with the rest of the family, but the only way he can survive is by abandoning the family and taking care of himself.
Antanas Rudkus (Dede Antanas) Jurgis' father. From the onset, he is determined to contribute to the family's success in Chicago; however, unlike in other countries, in the America he encounters the elderly are neither appreciated nor respected, and he dies destitute and deceived.
Stanislovas, Kotrina, Vilimas, Nikalojus, Juozapas, Kristoforas Elzbieta's children. Illustrating the abuse children suffered as a result of the industrial revolution, they all either die or are sent to work at much too young an age.
Antanas Rudkus (Little Antanas) Only child of Ona and Jurgis. He is Jurgis' hope for the future but he suffers a fate similar to his mother and cousins'.
Tamoszius Kuszleika A violinist. His passion for the violin exceeds his talent; for a while it seems that he and Marija might marry, but they are not destined to be together.
Jokubas Szedvilas A fellow Lithuanian immigrant. He owns a delicatessen and introduces Jurgis and his family to Packingtown.
The Widow Jukiene Jurgis' first landlady in Chicago. Twice Jurgis and his family are forced to rent "unthinkably filthy" rooms from her.
Mike Scully The democratic boss of Packingtown. Jurgis would not be so eager to work for the man if he knew the entire truth about Scully's involvement with Jurgis' family: Jurgis sees Scully as a powerful friend and ally, but actually Scully is both directly and indirectly responsible for the deaths of Ona and Little Antanas.
Phil Connor Ona's boss. He serves as a nemesis for Jurgis and illustrates the theory that might makes right. He also demonstrates that it is not what you know but who you know that counts.
Jack Duane Jurgis' cellmate. He introduces Jurgis to the criminal world of Chicago.
Madame Haupt Ona's midwife. This "enormously fat" woman is unable to save either Ona or her baby.
Freddie Jones Son of Jurgis' former boss. This drunken playboy provides Jurgis with an unforgettable evening and a $100 bill.
Buck Holloran and Bush Harper Members of Mike Scully's political machine who work with Jurgis. They make sure that they take care of themselves first.
Ostrinski A tailor. He introduces the world of socialism from the workingman's perspective.
Tommy Hinds Jurgis' final boss. This hotelkeeper is one of the organizers of the state Socialist Party, and his hotel is the site of many political discourses.
Lucas A traveling socialist speaker. Jurgis is one of the guests at a dinner party where this orator debates and defines socialism.
Nicholas Schliemann A socialist theoretician. He, along with Lucas, serve to state Sinclair's view of socialism. Although Jurgis hears him debate socialism with Lucas, he really exists as a way for Sinclair to talk to readers.