The great stage actor Richard Bennett had been brought back to films by Orson Welles for "The Magnificent Ambersons". Although his performance as old Major Amberson has become legendary, it was achieved with great difficulty, as Bennett, by then an old man near death, found it hard to remember his lines and his eyesight was too poor for him to be able to read them off cue-cards. Welles's patience in dealing with these problems has been widely described. When he cast Bennett in this film as the ship's captain, he overcame the problems very simply, by giving Bennett no dialogue at all, although the character has several memorable scenes. It was to be Bennett's final film role.
In late August 1942, RKO decided to delay the release of the movie because critics disliked it in press previews. By that time, Orson Welles' contract was terminated by a new studio head. As part of the settlement, Welles agreed to edit the last reel and to film additional scenes. He added the voice-over by Joseph Cotten throughout the movie and designed the sequence before the credits.
It is widely believed that Orson Welles directed this film, or at least large portions of it. However, in "This Is Orson Welles", he states he only acted in it and the directing credit should go to Norman Foster.
When production on Journey Into Fear began, co-stars Orson Welles and Dolores Del Río had been having an affair for several years. Del Rio ended the relationship shortly after the film's release.
The music that plays when Joseph Cotten escapes from a car is taken from RKO's "King Kong." Orson Welles liked using bits and pieces from other movie scores (years before Quentin Tarantino). He wanted to do this for "The Lady from Shanghai," but, to his chagrin, the producers used a melodramatic score that was a variation of a song they unsuccessfully attempted to popularize.