This is heavy, Doc. On July 3, 2025, Back to the Future celebrates its 40th anniversary. Great Scott!

Back to the Future was directed by Robert Zemeckis, written by Zemeckis and Bob Gale, starring Michael J. Fox, Christopher Lloyd, Lea Thompson, Crispin Glover, and Thomas Wilson. The movie tells the story of Marty McFly, a teenager and aspiring musician, with an unlikely friendship with scientist, Doc Brown. Late at night Marty meets Doc in an empty parking lot where Doc reveals his time machine in the form of a DeLorean, powered by plutonium in a flux capacitor. Doc shows Marty how the time machine works and sends Marty back in time to November 5, 1955.

Wandering through Hill Valley in 1955, a disoriented Marty meets his parents George and Lorraine and accidentally changes their future. He saves George from being hit by a car, getting knocked unconscious in the process, and wakes up to find his mother has become enamored with him. Marty is able to find Doc Brown, but since this is 30 years before Doc met Marty, it takes some persuading to convince him that Marty came back from the future and did so because Doc invented a time machine. To make things even more complicated, Marty’s interference in his parents’ lives means that he and his siblings could cease to exist unless he can get young George and Lorraine back together. Oh, and Marty also has to deal with Biff, the town bully.

Gale the co-writer and a producer on the film conceived the idea for Back to the Future while visiting his parents. He found his father’s high school yearbook and started wondering if he and his father would’ve been friends had they been teenagers at the same time. Once he returned to California he started discussing the concept with Zemeckis. The pair pitched the idea to Columbia Pictures, making a development deal for a script in the fall of 1980.

Gale and Zemeckis decided to send their lead character back to 1955 in part because it made mathematical sense and because that period saw the beginning of rock n’ roll and teenagers becoming culturally significant. They chose to use the DeLorean because it had a futuristic look and could be mistaken for a flying saucer by paranoid people of the ’50s. The writers smoothed out the odd friendship between Marty and Doc by creating the giant guitar amplifier, an invention of Doc’s that Marty loves, and the disturbing crush Lorraine has on Marty by having her say, “It’s like I’m kissing my brother.”

The first draft was finished in February 1981 but when Columbia read it, they considered it cute and warm, but not racy enough. Zemeckis and Gale took the script to other major studios, but it was rejected over and over again during the next four years. Most teen comedies in the early 1980s were much more mature-themed with sexual content, adult language, and drug use. They pitched the movie to Disney who said no because the storyline that saw the mother falling for her son was inappropriate for a family movie.

They considered approaching Steven Spielberg, but were hesitant since he had produced Used Cars and I Wanna Hold Your Hand, written by the pair, but they had both flopped. Zemeckis chose to direct Romancing the Stone, which became a box office hit. With his new Hollywood status, Zemeckis talked to Spielberg about the movie and it was set up with Universal Pictures as the distributor and Amblin Entertainment producing.

Eric Stoltz was originally cast as Marty McFly when filming began in November 1984. When producers watched early footage, they were not convinced that they had made the right choice by casting him in the role. There was also tension on set, because Stoltz was using method acting (i.e. staying in character even when the camera wasn’t rolling). He wouldn’t answer to his real name and there were conflicts with cast and crew, including Wilson. Stoltz was subsequently fired.

Fox joined the project and they began filming again in January 1985, while he was simultaneously filming episodes of Family Ties. Since Fox was so busy and also needed rest, the filmmakers would shoot some of Marty’s scenes without him to work out any issues, and then he’d film his part once the scene was fine-tuned. They wrapped filming in April 1985, and started cutting, editing, adding the score, effects, and other post-production work. The movie was originally planned for release in May, but needed to be pushed back to June, then met the July 3 release date.

Back to the Future was the number one film for seven of its first eight weeks in theaters. The movie was a big hit with viewers and film critics, soon becoming a trilogy that saw Marty and Doc travel to the future in 2015 and the past in 1885. The franchise expanded with an animated series in 1991-1992, a musical production, pinball games and video games, comic books, and a novelization.

Back to the Future is the type of movie that can be enjoyed by the whole family, and became a cultural touchstone enjoyed by several generations. Forty years later, fans still quote the movie, sing along to “The Power of Love,” and imagine joining Marty and Doc on a trip through time.