The two main characters are Philip Swallow and Morris Zapp. Both are 40-year-old white male English literature professors. The plot involves their switching positions in the United States and England.

Philip Swallow teaches at the University of Rummidge in the Midlands. He is a modest, obliging person without much professional ambition. Swallow is married to Hilary, who briefly accompanies him but then returns to England. He excels at teaching but has done little research. At the start of the novel, he lacks confidence, is eager to please, and is very suggestible. While teaching in Zapp’s spot at California’s University of Euphoria, he has affairs with Zapp’s daughter and his wife, Désirée, and gets caught up in the student protests.

Morris Zapp goes from his tenured post at University of Euphoria to teach at Rummidge. He is a celebrated expert on Jane Austen but largely uninterested in teaching. Zapp’s ego and inflated self-importance often help him get his own way. In England, he becomes more compassionate but has an affair with Swallow’s wife. His experience dealing with student protests comes in handy and gains him respect on campus.

Désirée Zapp is Morris’s estranged wife. The faculty exchange helps him stave off her request for a divorce after she has made him move out of their house. In his absence, she becomes involved in the women’s movement and has an affair with Philip, who moves in with her.

Hilary Broome Swallow is Philip’s wife; the couple married while they were students and have three children. Her primary roles are wife and mother. After returning to England, she re-evaluates the state of their marriage and then begins the affair with Zapp largely as retaliation for Philip’s cheating.

Melanie Byrd is Morris Zapp’s daughter. Swallow meets her without knowing this. Aside from their brief sexual relationship, she represents the youthful energy that revitalizes Swallow.