Elmer Gantry (Burt Lancaster) is a hard-drinking, fast-talking traveling salesman with a charismatic personality who infuses biblical passages and fervor into his pitches as a way to ease and collect money. He is drawn to the roadshow of Sister Sharon Falconer (Jean Simmons) and is immediately attracted to the revivalist's saintly aura. As the troupe leaves town for Kansas, Gantry sweet talks her naive assistant, Sister Rachel (Patti Page), into disclosing information regarding Falconer's past, which he uses to con his way into her good graces. He joins the troupe preaching "Christ in commerce" and how he is a saved salesman.