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Michael J. Fox had always been the first choice for Marty, but he was unavailable due to scheduling conflicts with his work on Family Ties (1982). As "Family Ties" co-star Meredith Baxter was pregnant at the time, Fox was carrying a lot more of the show than usual. The show's producer Gary David Goldberg simply couldn't afford to let Fox go. Robert Zemeckis and Bob Gale then cast Eric Stoltz as Marty based on his performance in Mask (1985). After four weeks of filming which added up to roughly 40 minutes of footage with Stoltz, Zemeckis, Gale, and Steven Spielberg felt that Stoltz wasn't right for the part, and Stoltz agreed and was still paid his full salary. According to various cast and crew members, Stoltz was taking the role way too seriously, playing it as if he was in a drama, and insisting everyone call him Marty on set even when the cameras weren't rolling. According to Tom Wilson who played Biff, most of the crew cheered when Stoltz was fired because they were so fed up with his behavior. By this stage, Baxter was back fully on Family Ties and Goldberg agreed to let Fox go off to make the film. Fox worked out a schedule to fulfill his commitment to both projects. Every day during production, he drove straight to the movie set after taping of the show was finished, and averaged about five hours of sleep. The bulk of the production was filmed from 6 p.m. to 6 a.m., with the daylight scenes filmed on weekends. Reshooting Stoltz's scenes added $3 million to the budget. After Fox arrived on set, Zemeckis said that not only did Fox fit the character and movie better but everyone else's performances around him improved as well.
The rights to the film and its sequels are owned by Robert Zemeckis and Bob Gale. In a 2015 interview, Zemeckis maintained that no reboot or remake of the film would be authorized during his or Gale's lifetime.
Writers Bob Gale and Robert Zemeckis actually received a fan letter from John DeLorean after the film's release, thanking them for immortalizing his car.
The script was rejected 44 times before it was finally green-lit.
In 2010, during a cast reunion, Michael J. Fox said that strangers still call him "McFly!" constantly. Fox said that the most remarkable instance was when he was in a remote jungle in the South Asian country Bhutan, located between China and India in the eastern Himalayas. A group of Buddhist monks passed him and one of them looked at Fox and said, "Marty McFly!"
Crispin Glover claimed to have seen the film only once, shortly after its release. In contrast, Christopher Lloyd stated that when he stumbles across a Back to the Future film while channel surfing, he often sits and watches it.
Huey Lewis: When Marty is being judged at the band auditions at the beginning, the judge who stands up to say he is "just too darn loud" is Huey Lewis, whose songs, "The Power of Love" and "Back in Time" are featured on the movie's soundtrack, and also wrote Marty's audition song (which is a re-orchestrated version of "The Power of Love.")