Howard Hawks was the original director, but was fired from the project after his previous film, Bringing Up Baby, was a box office bomb.
Sabu was first choice to play Gunga Din; when it became clear he was unavailable, Sam Jaffe was hired in his place. In an interview years later, Jaffe (a Jewish Russian-American) was asked how he so convincingly played an Indian Hindu. Jaffe replied he kept telling himself to "Think Sabu."
At the time he was playing water-boy Gunga Din, Sam Jaffe was 47 years old.
Bits and pieces of the film's use of Lone Pine's boulder-strewn area remain, including the anchors for the rope bridge across the "chasm". Some judicious referencing of the film, and stills from it, make for an interesting tour of the area to locate where a number of the scenes were shot.
Budgeted at $1.915 million, this was the most expensive film RKO had produced to date.
Director George Stevens had Douglas Fairbanks Jr. and Cary Grant flip a coin for the role of Cutter. Grant won.
Director George Stevens' flair for comedy in this film is no accident. As a cameraman for Hal Roach, he filmed shorts with Stan Laurel and Oliver Hardy, was doubtless a friend of Charley Chase and had directed some of the "Boy Friends" shorts before his association with this film.
Eight make-up artists were sent to the Lone Pine set, where they worked for the six weeks of location shooting. Over 600 extras were employed in the Mount Whitney scenes.
In March 1939, the Kipling family objected to a reporter being called Rudyard Kipling, prompting RKO to eliminate that scene from the film when it was re-released. However, it is in the prints available today. The scheduled release date of December 1938 was postponed for retakes. John Sturges, an uncredited editor on this film, directed the remake, Sergeants 3.
In some prints, the actor playing Rudyard Kipling, has been replaced on one side of the screen by a rather shaky matte when the last lines of poem "Gunga Din" are read.
Inspired a comedy recording, "The Last Blast of the Blasted Bugler", by Sonny Giannotta, released on ABC Records in 1962.
Mention is made of Chandragupta Maurya as a significant Indian soldier. He founded the Maurya empire, unifying much of India and becoming its first emperor.
The "bridge over the deep chasm" scene, in which Annie the elephant shakes a rope bridge while trying to cross, was actually filmed on a bridge eight feet off the ground. The background was a realistic painting of a chasm.
The battle between the Thuggees and the British Indian army was added when RKO considered the ending too bland.
Upon release a campaign was launched by the Indian magazine "Filmindia" against the misrepresentation of Indian caricatures in the film, and the displaying of insensitivity towards Hindu customs. Following riots in India and Malaya the film was withdrawn by the censors.
Was second only to Gone with the Wind as the biggest money-maker of 1939.