According to a news item in HR, Judith Anderson and Scotty Beckett were originally cast as Mrs. Roth and one of her sons, but were replaced because they were unsuited for the roles. Additional news items in HR state that the special mountain snow scenes were filmed at Salt Lake City, UT by Leonard Smith and Lloyd Knechtel and that other scenes were shot at Sun Valley, ID. Modern sources credit Richard Rosson with the second unit direction in Sun Valley. In August 1940, a HR article reported that writer Al Rosen filed a lawsuit against Loew's, Frank Borzage, Claudine West, Anderson Ellis and George Froeschel, among others, for incorporating the plot of his novel Mad Dog of Europe into The Mortal Storm. HR added in Mar 1943 that he was still seeking an injunction, damages and impounding of the film, but the outcome of the case has not been determined. An unidentified contemporary source contained in the Production Files at the AMPAS Library noted an unconfirmed report that the Nazis banned all M-G-M films because of this film. The film was included in FD 's "ten best" list for 1940. HR reported in Apr 1942 that The Mortal Storm was the first anti-Nazi film to run in Brazil, where it broke box-office attendance records.
       A modern source credits Victor Saville as producer and indicates that Saville refused onscreen credit because he was British and did not want to be accused of inciting America to war. According to an article in LAEx on 10 Sep 1941, Senator Gerald P. Nye wanted to summon Saville to testitfy before a sub-committee investigating "British agents operating in the film industry." In the modern article, Saville claims that he directed parts of the film; however, another modern source, that includes interviews with James Stewart, Robert Stack and Gene Reynolds, indicates that those actors refute Saville's claim that he worked as a director on the film. Modern sources credit Henry S. Noerdlinger as technical director and Bronislau Kaper with additional music for the film. A few scenes from the film were included in the 1992 Twentieth Century-Fox picture Shining Through, directed by David Seltzer, and starring Michael Douglas and Melanie Griffith