The main character of The Jungle, Jurgis, is the only character to appear in every chapter. Although most of the action in the text is shown from his perspective, readers actually gain very little insight into Jurgis' innermost person. This does not mean, however, that as a character he is not a sufficient study. Indeed, because readers have no firsthand knowledge of Jurgis' thoughts, beliefs, feelings, and passions, he is quite different from most characters in modern novels — he is neither developed nor complex — but he is still worthy of analysis.
Sinclair primarily depicts Jurgis as a protagonist as defined by Emile Zola; that is, one who is the victim of chance and whose fate is determined by forces beyond his control. Because Emile Zola both created and mastered this type of fiction, the style is known as Zolaism (and is also called naturalism). At the end of the novel, however, Jurgis does experience a change, and becomes a dynamic character; one who is pro-active and embraces socialism as a means of escaping the drudgery of his existence.
From the onset, and throughout the entire text, Jurgis is shy and awkward at social functions. This is a mark of his staunch individualism, a trait simultaneously beneficial and harmful to him. Early on he is a strapping young man, full of vigor and life, and is able to carry himself through any adversity. This physical description provides more insight into his character because Jurgis experiences both a physical and emotional change. Gradually, the difficulties he encounters wear him down. In one sense, The Jungle is similar to a medieval morality play, and Jurgis is a contemporary "Everyman." The characters in morality plays were symbolic representations, used to illustrate an idea; Jurgis represents all immigrants. His experiences are typical of immigrants, and his struggles are their struggles. By presenting Jurgis in a sympathetic light, Sinclair enables readers to embrace all immigrants. The Jungle reveals the problems that all immigrants and poor people suffer, and presents socialism as the solution.
In addition to being an Everyman, Jurgis is a literary naïf, or naïve person. He starts out as innocent and trusting, but gradually grows wise to the ways of the world. Jurgis' transformation is gradual, mirroring his gradual acceptance of socialism. Before Jurgis is able to exploit the system, the system must exploit him. Before he can accept socialism, he must experience and be victimized by another economic system, in this case, capitalism. Through experience, Jurgis learns that everything is not as it seems, and that blind faith is not necessarily a good thing.
As Jurgis grows distrustful of the economic system in which he is enslaved, he realizes that he enjoys his family, particularly his son, only when he's not working. Unfortunately, for Jurgis and his family, when he is unemployed, his family suffers financially. This relates to a larger theme — the effect the capitalistic system has on both workers and the family unit. Jurgis' relationship with his family demonstrates that the capitalistic system, of which he is enslaved, is contrary to and in fact destroys the family unit.
Jurgis' personal loss of family leads to his own rebellion. His first action — destroying peach trees — is reactive, striking out against the farmer's insults. Eventually, Jurgis becomes proactive, but his life of crime is not very productive. After he returns to the city, Jurgis becomes as much a man for hire as Ona had been, illustrating the double standard of the day. Jurgis' life of crime is his attempt at getting back at the city that got him. Nevertheless, his old feelings remain, and when he sees Connor again, Jurgis' true feelings about the sanctity of marriage and love of family re-surface.
Later, discovering the truth about Marija enables Jurgis to establish more firmly his true feelings about what is right and wrong in the world. Because he was unable to save Ona, he longs to save Marija. Attending a socialist meeting by chance leads Jurgis to rebel constructively. By the end of The Jungle, Jurgis is satisfied with his place in society and is confident that he can help improve society for everyone. He realizes that alone, as an individual, he cannot expect to accomplish much; however, as an individual who comprises part of a larger group, he can accomplish many things. In the beginning of the novel, Jurgis is driven by his desire to work harder; at the end of the novel, he is driven by the desire to work harder for the socialist movement.