After several years as a traveling salesman of farm equipment, he becomes a confidante of Sharon Falconer, a popular motivational speaker and evangelist with a "road church" show. Gantry becomes her lover, but loses both her and his position when she and scores of attendants are killed in a tragic fire in her tent tabernacle. After this catastrophe, he briefly acts as a "New Thought" evangelist, and eventually becomes a Methodist Minister. He marries a local parishioner, although he is unhappy with her sexual frigidity, and uses her for appearances only. Years later the Methodist leadership awards him a larger congregation in Lewis's fictional city of Zenith. With his power and career in full tilt, Gantry manipulates local, state and national politics which involves police raids against bootleggers and bar patrons. His corruption and power hunger contribute to the downfall, physical injury, and even death of key people around him, including Frank Shallard, a sincere minister who questions the moral purpose of the evangelical church. Shallard, a former associate, is nearly beaten to death by a lynch squad of Gantry loyalists who were angered by his "atheistic" divergences in Christian teachings.
Especially ironic is the way he champions love, an emotion of which he seems incapable, in his sermons; preaches against ambition, when he is so patently ambitious; and organizes crusades against (mainly sexual) immorality, when he has difficulty resisting sexual temptations.