"Pard" played by "Zero the Dog" was Humphrey Bogart's dog in real life.
"The Screen Guild Theater" broadcast a 30 minute radio adaptation of the movie on April 17, 1944 with Humphrey Bogart and Ida Lupino reprising their film roles.
"The Screen Guild Theater" broadcast a 30 minute radio adaptation of the movie on January 4, 1942 with Humphrey Bogart reprising his film role.
Humphrey Bogart's part in this movie was originally intended for Paul Muni. Muni did not like the first draft of the screenplay which was authored solely by John Huston and given to him by Hal B. Wallis, so Wallis got the book's author, W.R. Burnett, to assist Huston in a second rewrite. This was presented to Muni who still disliked it and turned the movie and the role down completely. In the meantime, On May 4th, 1940, Bogart sent a telegram to Wallis reiterating his continuing desire, which he had mentioned several months earlier, to play the part of Roy Earle. After Muni turned down the script the next person on the list for Warner Brothers was George Raft. Bogart, knowing that Raft was trying to change his image and move away from gangster roles, found out about this and mentioned to Raft when he saw him next that the studio was trying to get him do another gangster movie where the gangster gets shot at the end. Raft marched into Wallis' office and flatly refused to do the movie. Bogart finally ended up with the role he wanted all along by default.
In addition to Hal B. Wallis, Humphrey Bogart also sent several telegrams to studio head Jack L. Warner, begging to be cast as Roy Earle. After Paul Muni left Warner Bros. in a contract dispute and George Raft also turned down the role, Warner called Bogart and told him the part was his...on the condition that Bogart stop sending him telegrams.
In the climactic scene, Humphrey Bogart's character slides 90 feet down a mountainside to his death. His stunt double, Buster Wiles, bounced a few times going down the mountain and wanted another take to do better. "Forget it," said Raoul Walsh. "It's good enough for the 25-cent customers."
The rights to W.R. Burnett's novel were snapped up within two weeks of its publication.
This was the last movie Humphrey Bogart made where he did not receive top billing. The studio thought that Ida Lupino should have top billing given the fact that she had been such a big hit in They Drive by Night and so her name ended up above Bogart's on the title card. Bogart was reportedly unhappy about receiving second billing but never complained.
When Ida Lupino found herself unable to cry during the film's final scene, co-star Humphrey Bogart coaxed her into it by telling her, "Listen, doll, if you can't cry, I'm going to take the picture away from you." Despite this, Lupino disliked Bogart's verbal treatment of her, and refused to accept another co-starring role with him in Out of the Fog. He was replaced by John Garfield.
When Pa first meets Roy at the gas station, Pa says, referring to an accident he almost had, "A jackrabbit jumped in front of the car and I kinda lost my head." Director Raoul Walsh lost an eye a dozen years earlier when a jackrabbit jumped through the windshield of the car he was driving.