Errol Flynn was initially excited about going to India, and turned down the studio's offer of the lead in King Solomon's Mines (1950), which ultimately went to Stewart Granger. However all of Flynn's scenes in this film were shot in the studio and matched in the editing room with long shot second unit footage of his double.
MGM originally announced the film in 1938 as a vehicle for Freddie Bartholomew and Robert Taylor, but World War II saw this put on hold. In 1942 it was reactivated to star Mickey Rooney, Conrad Veidt (as Red Lama) and Basil Rathbone. However this was postponed out of fear of offending Indians, and also war-time allies the Soviets. In 1948 the Indian government approved the film and the Cold War meant it was permissible to have Russian villains.
The film could not be made during World War II as it was considered pro-British Empire and anti-Russian.
Although the movie was financially successful, the 40-year-old Errol Flynn was widely considered too old for his character, as well as miscast as an Indian.
Richard Hale serves as omnipotent offscreen narrator in the first half of the film and serves in character as Flynn's disloyal employee Hassan Bey. However, even though they are ostensibly different people, the narration stops after Bay is killed.
In the master shot of the scene in which Flynn enters the tent with a bowl of food for Dean Stockwell for the lama, practical joker Flynn had piled it high with steaming fresh camel dung. Stockwell played the scene as written but it cost Flynn $500 because he had bet with the crew that he could make the young actor crack up laughing.
According to Dean Stockwell in a 1985 interview, "There were uglies and there were beauties. For me, Errol Flynn was the best. I didn't know anything about sex or what manhood was - and he opened that door for me."
"Lux Radio Theater" broadcast a 60 minute radio adaptation of the movie on February 18, 1952 with Errol Flynn and Dean Stockwell reprising their film roles.
The Wilhelm scream is heard twice when Mahbub Ali and Kim roll a large rock down a hillside causing a landslide and supposedly crushing the attacking warriors.
Originally bought as a property for Freddie Bartholomew in 1938. Production was so far under way (including Bartholomew posing with Indian elephants for newsreel cameras), that the project was eventually abandoned to save costs. In 1942 it was revived as a property for Mickey Rooney but it too was abandoned at behest of the Office of War Information because of its imperialistic theme.
In the short scene where Lurgan Sahib is testing Kim's mental abilities in the museum armory, a bright silver Winkie Guard's spear from The Wizard of Oz is prominent in the display behind Kim.