Babbitt follows George F. Babbitt, a forty-six-year-old real-estate broker in the fictional Midwestern city of Zenith around 1920. He sells houses for more than people can afford, lives in a tidy Dutch Colonial in the suburb of Floral Heights, and surrounds himself with the latest advertised goods. The opening chapters track an ordinary morning in minute detail, and the comedy comes from how completely Babbitt's tastes and beliefs have been supplied to him from outside.
Zenith runs on boosterism. Babbitt belongs to the Boosters' Club, the Athletic Club, and the Chatham Road Presbyterian Church, and he prizes being a Good Fellow and a Regular Guy above almost anything. Lewis stages set-piece speeches, banquets, and a real-estate-board address in which civic pride, business slang, and suspicion of anyone called a liberal or radical all blur together. The praise of efficiency, prohibition, and prosperity is recorded so faithfully that it becomes its own indictment.
Beneath the confidence Babbitt is restless. His closest friend, Paul Riesling, hates the standardized city and feels trapped in his marriage and his work. When Paul finally shoots his wife and is sent to prison, the one person who shared Babbitt's private doubts is taken away, and Babbitt is left exposed to his own dissatisfaction.
Babbitt then rebels. He drifts into a circle of bohemians around Tanis Judique, drinks against the prohibition laws he publicly praises, dabbles in sympathy for a strike and for the radical lawyer Seneca Doane, and holds back from the new Good Citizens' League. His old friends notice. The pressure builds quietly through cooled greetings and lost business until the cost of nonconformity becomes plain.
In the end the town reclaims him. After his wife falls ill, Babbitt makes peace with his friends, joins the League, and slips back into the net he had tried to escape, even rejoicing in the trapping. The book closes on his son Ted, who marries young and walks out of college to work in a factory. Babbitt cannot free himself, but he privately admits he has never done a single thing he wanted, and tells Ted to go ahead where he could not.