Back to the Future reigns as one of the most famous film franchises in history. The year 1985 has become a staple in pop culture (even a song by SR-71 is titled after the year), and one of the most iconic figures from that era is Marty McFly: a high school student who travels to the future, then the past, in all three movies. Though the world knows Michael J. Fox brought the character to life, some don’t realize that the role was initially given to Eric Stoltz, whom Michael replaced weeks after production had already begun.

Now that Michael has released his book, Future Boy, which details his hectic schedule balancing Back to the Future and Family Ties, the Parkinson’s Disease advocate revealed what actually happened when he replaced Eric.

Here, Hollywood Life has the breakdown of why Michael replaced Eric and how the two really feel about each other.

Original “Marty McFly” actor Eric Stoltz on being fired from Back to the Future (1985) pic.twitter.com/G0AyPW7hCX

— Eyes On Cinema (@RealEOC) February 28, 2025

Why Did Michael J. Fox Replace Eric Stoltz as Marty McFly?

Michael was the original choice to play Marty in Back to the Future, but his obligation to the Family Ties filming schedule took priority. So, Eric was cast in the role but was replaced by Michael because director Robert Zemeckis envisioned a more comical portrayal of Marty. Eric brought more of a deeper, emotional substance to the character.

Via Entertainment Weekly, Michael wrote in Future Boy, “They had already shot for over a month. Unfortunately, the dailies were disappointing. Eric was an immensely talented actor, but the creative team felt that he just wasn’t the right fit for Marty McFly.”

Michael’s co-stars have also weighed in on the production team’s devastating decision to replace Eric weeks after they had already begun filming. Per Digital Spy, Christopher Lloyd (who played scientist Doc Brown) previously said he “felt for Eric” when he was let go.

I know it’ll never happen ‘officially’…but I still hold out hope that one day we’ll get to see an alternate cut of Back to the Future with Eric Stoltz as Marty McFly, given that roughly 80% of filming was complete. pic.twitter.com/eufo472kR2

— Mark’s Yesterworld (@Yester_World) January 19, 2023

“He was a really good actor,” Christopher noted, before adding, “Although he was doing the part well, he was not bringing that element of comedy to the screen.”

Lea Thompson had similar remarks, per Digital Spy. The actress, who played Lorraine McFly in Back to the Future, had worked with Eric on the 1984 movie The Wild Life and admitted it was “hard” to see Eric go.

“It was hard for me because I was really good friends with Eric,” Lea previously said. “Eric is such a different actor and he could be very difficult. … [He] had such an intensity. He saw drama in things. He wasn’t really a comedian, and they needed a comedian. He’s super-funny in real life, but he didn’t approach his work like that, and they really needed somebody who had those chops.”

Was Eric Stoltz Fired From Back to the Future?

Yes, Eric was, indeed, fired from Back to the Future, but not because of any bad blood with the production. As previously noted, Michael was chosen to replace Eric because the creative team wanted an actor with a more comical approach in playing Marty.

Are Michael J. Fox & Eric Stoltz Friends?

Yes, Michael wrote in Future Boy that he reached out to Eric 40 years after he took the Pulp Fiction actor’s place as Marty. In one excerpt, Michael noted he “was prepared for the likelihood” that Eric would “prefer” to remain silent on the matter. The fellow actors had never met before Michael reached out.

“If your answer is ‘piss off and leave me alone’… That works, too,” Michael wrote to Eric, he revealed in his book. However, Eric responded with a “beautifully written reply,” which jokingly began with, “Piss off, and leave me alone! I jest.”

“Eric was thoughtful about my outreach, and although he respectfully declined to participate in the book, he seemed open to the idea of getting together,” Michael explained in his book.

After Eric visited Michael at his New York home, it was clear to both of them that “neither of us had an issue with the other,” the Teen Wolf star wrote in Future Boy. 

“What transpired on Back to the Future had not made us enemies or fated rivals; we were just two dedicated actors who had poured equal amounts of energy into the same role,” Michael noted. “The rest had nothing to do with us. As it turned out, we had much more in common than our spin as Marty.”