The ages of the cast and characters in Back to the Future are a bit convoluted, given that the movie takes place in two different timelines and some actors play their roles as teenagers and adults. The science action film premiered on July 3, 1985, and depicted a teenager accidentally traveling back in time (to 1955) via a DeLorean time machine that his older scientist friend built. Unfortunately, while there, he accidentally interferes with the timeline and threatens his own existence when he comes across his parents as teenagers.
The movie was an instant success, and some of the cast returned for two sequels — Back to the Future Part II and Back to the Future Part III — while others were recast. However, most critics and fans agree that the original film is not only the best in the series but also one of the best science fiction (and time-traveling) movies ever made. Its success could be attributed to its unique story, humor, and the main cast members’ performances, especially Michael J. Fox as Marty McFly and Christopher Lloyd as Doc Brown.
6 Michael J. Fox (23) As Marty McFly (17)
Michael J. Fox starred as Marty McFly, one of the most iconic movie characters ever created, in the 1985 science fiction film. However, he was not the original Marty actor in Back to the Future. Instead, Eric Stoltz was cast in the role, and the cast and crew even filmed many of their scenes with Stoltz as Marty. Director Robert Zemeckis determined that Stoltz’s approach to the character was not right (he was more serious, while the filmmakers wanted Marty to be light-hearted). As a result, Stoltz was fired, and Fox, the producers’ first choice to play the protagonist, was cast.
Fox, who was initially busy when first approached to star in Back to the Future, was 23 years old when he shot his scenes for the movie in early 1985. Meanwhile, the actor’s character was 17 in the film. The age difference between the two was not significant, so Fox was able to believably play a teenager in high school who traveled 30 years into the past by accident.
5 Christopher Lloyd (46) As Emmett “Doc” Brown (35 & 65)
Unlike Michael J. Fox, Christopher Lloyd (and the rest of the cast) were chosen for their parts from the very beginning of production on Back to the Future. Lloyd portrayed Emmett “Doc” Brown, an eccentric scientist who used a DeLorean to create a time machine, in the popular movie. Marty had been acquainted with Doc since he was 14, so he was used to his bold ideas and mad inventions. However, nothing could have prepared Marty for Doc’s time machine to send him back to 1955, where he had to explain who he was to the scientist 27 years before the two friends met.
Like many of his cast mates, Lloyd played his Back to the Future character at two different ages — 65 years old in 1985 and 35 years old in 1955. However, in real life, the actor was 46 while filming the movie in late 1984 and early 1985. Lloyd would go on to reprise his role in Back to the Future Part II and Back to the Future Part III.
4 Lea Thompson (23) As Lorraine Baines McFly (17 & 47)
Lea Thompson was the same age as Michael J. Fox — 23 years old — while shooting her scenes for Back to the Future. But unlike her costar, Thompson had to look like she was 17 while filming the 1955 parts and 47 in the 1985 section of the movie. The actress played Lorraine Baines McFly, Marty’s mother, when she was a similar age to her character and when Lorraine was 24 years older than Thompson in real life. As a result, Thompson wore makeup that made her look much older than she truly was.
When the audience first met Lorraine in Back to the Future, she lived a drab life in the ’80s. But when Marty traveled to 1955, he encountered a much different version of his mother (who may or may not have had a crush on him). Unfortunately, Marty messed with the timeline and almost prevented his parents from getting together. But Marty was able to right his wrongs and go back to the future, where he met a more lively version of Lorraine.
3 Crispin Glover (20) As George McFly (17 & 47)
Crispin Glover was one of the youngest actors in the Back to the Future cast, as he was 20 years old during principal photography (though he turned 21 toward the end of production). Glover played George McFly, Marty’s father and Lorraine’s (future) husband, in the science fiction film, and like Lea Thompson, the actor had to portray his character when he was 17 in 1955 and 47 in 1985. Of course, Glover was closer in age to the 1955 version of himself, so he had to don makeup to make him look older for the scenes set in 1985.
While trying to push his parents to get together in 1955, Marty attempted to teach George how to be cool (and less creepy than he had been while crushing on Lorraine). Eventually, Marty succeeded, and George won over Lorraine’s heart. When Marty traveled to the future, his father had changed just like his mother had. Instead of being the docile man Marty once knew, George was confident and a successful science fiction writer.
2 Thomas F. Wilson (25) As Biff Tannen (18 & 48)
Thomas F. Wilson starred as Biff Tannen, the antagonist of Back to the Future. Biff was a bully who had been picking on George McFly his whole life, from when they were classmates in high school to when Biff became George’s boss as an adult. So, when Marty traveled back to 1955, he also had to deal with Biff. Wilson was 25 years old while shooting Back to the Future, and like Lea Thompson and Crispin Glover, the actor portrayed his character at two different stages of his life. Biff was 18 in 1955 and 48 in 1985, meaning that Wilson had to wear makeup to make himself look 23 years older in the 1985 scenes. Related: Back To The Future’s Unused Ending Would Have Totally Ruined George McFly
1 Claudia Wells (18) As Jennifer Parker (17)
Claudia Wells played Jennifer Parker, Marty’s girlfriend, in the 1985 science fiction film. While most of her costars were involved in scenes in both of the movie’s time periods, Wells only appeared in the 1985 sequences. The actress was the Back to the Future cast member who was closest in age to her character because Wells was 18 years old while filming, and Jennifer was 17 in the movie.
