Steven Spielberg was one of the producers but it’s always Robert Zemeckis and Bob Gale who get the most creative credits for the movie. What creative contributions did Spielberg make to the film?
shareSpielberg decided that one of Lorraine's brothers should wear a coonskin tail hat at the dinner table.
shareRobert Zemeckis was lumbered with Eric Stoltz. He never wanted him, he wanted Michael J. Fox but couldn't get him because Fox was basically carrying Family Ties at that time while Meredith Baxter was having a baby. Universal executive Sid Sheinberg wanted Stoltz (because of Mask) over the other choices like Charlie Sheen, Ralph Macchio etc.
Stoltz did just over four weeks of filming from November 26th 1984 - December 30th 1984 before Zemeckis realized he wasn't getting the performance out of him he wanted and it was time to replace him. Baxter had returned to Family Ties so Fox's schedule was a bit more flexible and Fox agrees to do BTTF but the transition couldn't happen instantly so without telling Stoltz, Zemeckis and the rest of the crew (who saw Stoltz being fired as good news) were filming around him. They're not filming Marty during his exchanges with the likes of Doc and the others, they're just filming footage of them, and the set designers were told not to properly dress the sets he's filming on.
Zemeckis fires Stoltz on January 10th, Fox starts on January 15th. Because of all this, filming had fallen 34 days behind schedule, the budget had increased by nearly 4 million, while Stoltz still got his full salary.
The point to all this? I think this was allowed to happen precisely because of Spielberg being executive producer and good friends with Zemeckis and having the clout and influence to get away with such a messy shoot. It's not as if Zemeckis had done big influential films or blockbusters like Spielberg had before this. So I think we got the perfect actor for Marty McFly because of him.
In the March 1989 issue (#58) of a French magazine called Mad Movies, there was this exchange between the interviewer and Eric Stoltz…
Q: Do you remember your experience on Back to the Future? You were originally hired to play the Michael J. Fox role and it only lasted a week or two…
A: Six weeks! I remember a miserable and very unpleasant experience. The director, Robert Zemeckis, and I were not on the same wavelength. For example, he loved Huey Lewis and the News and I didn’t find it hot. I don’t remember much else, it was so long ago. On the other hand, Christopher Lloyd was on the same wavelength.