This film saved the famous love song "As Time Goes By" from being removed from Casablanca (1942). Ingrid Bergman began filming this movie immediately after completing "Casablanca". For this role, her hair was cut short. Meanwhile, for "Casablanca", Warner Brothers wanted to substitute another song for "As Time Goes By" and re-shoot some scenes with Bergman. However, since her hair had been cut, there would be a problem with continuity (even if Bergman wore a wig), so the idea was dropped.
When Ernest Hemingway told Ingrid Bergman she would have to cut off her hair for the role of Maria, she shot back, "To get that part, I'd cut my head off!" She would rehearse tirelessly until all hours of the night, begging to repeat a scene long after the director was satisfied.
Writer Dudley Nichols depoliticized the screenplay, removing all references to Gen. Francisco Franco, loyalists and Falangists. However, he did keep in one prophetic comment about how Germany and Italy were using Spain as target practice.
The book (and movie's title) is taken from John Donne's "Meditation XVII" from 1624: ..."No man is an island, entire of itself... any man's death diminishes me, because I am involved in mankind; and therefore never send to know for whom the bell tolls; it tolls for thee."
At the film's conclusion, Gary Cooper's horse falls and breaks its leg. The only horse the crew could get to do the stunt was brown, but Cooper's horse throughout the film was gray. Rather than re-shoot much of the film, Cooper's brown stunt horse was painted gray.
One of over 700 Paramount productions, filmed between 1929-49, which were sold to MCA/Universal in 1958 for television distribution, and have been owned and controlled by Universal ever since. It received its television premiere in San Francisco Monday 5 January 1959 on KPIX (Channel 5), launching the MCA/Paramount Library on that channel. It was broadcast in color, a rarity at that time, particularly for a CBS affiliated station, when color television was still in its infancy and vintage feature films rarely were granted that courtesy and expenditure. After this initial telecast, and its next one in Omaha 3 March 1959 on KETV (Channel 7), the film was withdrawn from television in deference to the forthcoming CBS Playhouse 90 production, highly publicized as the most ambitious television dramatic presentation of the season, to be broadcast in two parts, Thursday 12 March 1959 and Thursday 19 March 1959. The film's eventual widespread local television broadcasts resumed in Milwaukee 11 April 1959 on WITI (Channel 6), in Minneapolis 7 August 1959 on WTCN (Channel 11), in Johnstown 8 November 1959 on WJAC (Channel 6), in Toledo, in two parts, Monday-Tuesday 9-10 November 1959 on WTOL (Channel 11), in Grand Rapids 12 November 1959 on WOOD (Channel 8), in Asheville 15 November 1959 on WLOS (Channel 13), in Detroit 26 November 1959 on WJBK (Channel 2), in St. Louis 12 December 1959 on KMOX (Channel 4), in Philadelphia 25 June 1960 on WCAU (Channel 10), in Los Angeles 12 November 1960 on KNXT (Channel 2), in Chicago 17 February 1961 on WBBM (Channel 2), and, finally, in New York City 19 May 1961 on WCBS (Channel 2). Since color broadcasting was still in its infancy and limited to only a small number of high rated, mostly live programs, primarily on NBC and NBC affiliated stations, except for its initial telecast in San Francisco, all these film showings were all in B&W. Television viewers were not offered the opportunity to see vintage feature films in their original Technicolor until several years later. The DVD was first released by Universal 1 June 1999 and was re-released 19 May 2015. Cable TV viewers now also have the opportunity to watch it occasionally on Turner Classic Movies.
The first of three films in three successive years that were nominated for the Best Actress Oscar for Ingrid Bergman as well as Best Picture and Best Actor. The other two are: Gaslight (1944) and The Bells of St. Mary's (1945). Ingrid Bergman won Best Actress for Gaslight.
The producers, Buddy DaSylva and Sam Wood and the director Sam Wood's second choice for Maria was Lenore Aubert had Bergman turned it down. DaSylva and Wood told Aubert they were either going to go with only Bergman because she was a big star or with Aubert who wasn't as well known yet the way Selznick and George Cukor did with Vivien Leigh who at the time " Gone With The Wind " was being cast was not as big a star as Joan Bennett, Jean Parker or Paulette Goddard.
In the Hemingway novel, Robert Jordan makes his last stand with a submachine gun (most probably a Thompson, or "Tommy Gun"). In the film, the weapon is a Lewis machine gun, a larger, heavier and usually crew-served weapon.
"Helen Thimig, who is Mrs. Max Reinhardt in private life, is testing for the role of Pilar in 'For Whom the Bell Tolls' ..." (Newspaper Enterprise Association, "Erskine Johnson's Hollywood," The San Bernardino Daily Sun, San Bernardino, California, Sunday 8 February 1942, Volume 48, page 16.) She did not get the role.