The narrative follows the rise of Elmer Gantry, a charismatic and opportunistic man who exploits religious institutions for personal gain and social status. Gantry transitions from a dissolute college athlete to a prominent minister, navigating the hypocrisy of early 20th-century American evangelical movements. His objective is the accumulation of power and influence, which he pursues through manipulation and public performance. The story is presented through a third-person perspective that highlights the disconnect between Gantry's private vices and his public persona, set against the backdrop of a rapidly changing American religious landscape.

Readers and critics frequently highlight the novel's biting critique of religious hypocrisy and the commercialization of faith. Discussion often centers on the effectiveness of Sinclair Lewis's characterization of Gantry as a man devoid of genuine belief yet highly skilled in the art of persuasion. Many observers note that the pacing remains consistent as the narrative moves through Gantry's various professional iterations. The work is often cited for its enduring relevance in discussions regarding the influence of charismatic figures on public institutions. Readers frequently emphasize the stark contrast between the protagonist's internal cynicism and his external success as the primary driver of the book's thematic weight.