When he first learned that Richard Brooks was interested in adapting his novel, Sinclair Lewis told him that he should change it significantly, advising him to read all the criticisms of the book and use them as a way to improve on it.
After this film was released, Burt Lancaster got a letter from a boyhood friend he had not heard from in years. The friend wrote him that Lancaster's part in this film was the closest to the way Lancaster acted in real life when they were kids.
Pat Hingle landed the title role, but before filming began, he became caught in a stalled elevator in his apartment building. He lost his balance while trying to crawl out and fell 54 feet down the shaft. He sustained massive injuries, including a fractured skull, wrist, hip and leg, and several broken ribs. He also lost his little finger on his left hand. Hingle spent much of the next year relearning how to walk and was forced to give up the part in order to recover from his horrific injuries.
Jean Simmons became so frightened in the fire scene with burning pieces of balsa wood falling all around her that she ran off the set. Richard Brooks didn't know what to do, so Arthur Kennedy suggested getting the actress 'bombed' on gin and milk. Kennedy had used the strategy on a nervous 'Dorothy McGuire' in a scene from A Summer Place (1959). After five drinks in her dressing room Simmons performed as scripted.
Director Richard Brooks did not want Shirley Jones for the role of Lulu Bains, but Burt Lancaster insisted. As a result, Brooks gave Jones no direction in the filming of a very difficult scene. Brooks eventually admitted to her that he couldn't see anyone else in the role.
In a hate-filled sermon, Gantry denounces a number of "heresies" including "Russellism". This is a reference to Charles Taze Russell, first president of the (current) Watchtower Bible and Tract Society, the legal organization used by Jehovah's Witnesses.
George F. Babbitt, the main character in Sinclair Lewis' 1922 novel "Babbitt", is a minor character in "Elmer Gantry". His character is the one most responsible for bringing Sister Sharon's revival to his home town of Zenith and just so happens to be the brothel's landlord.
Sister Sharon is seen briefly outside a movie theater advertising a film. The title is not given but the stars names are given as Rudolph Valentino and Agnes Ayres, suggesting that the film is almost certainly The Sheik (1921).
In an effort to appease the Hays Code, a number of changes were made to omit controversial aspects of the book. In the original novel, Gantry was an ordained minister, but since the Code was against negative portrayals of priests, this element was entirety omitted.
Because of the success of the novel, it was adapted by Patrick Kearney into a play, which opened in New York City on 7 August 1928 and closed in September 1928 after 48 performances. The title role was played by Edward Pawley and Sharon Falconer was played by Vera Allen.
"Elmer Gantry" was originally intended to be screened on BBC 2 on November 18, 1987, but the horrific fire at King's Cross Tube station led to its cancellation due to the similarities of the big top fire in the movie.