Gale was born in University City, Missouri, the son of Maxine (née Kippel), an art dealer and violinist, and Mark R. Gale, an attorney. He is the oldest of his two other brothers, Charlie Gale, who screenwrote the film Ernest Scared Stupid, and Randy Gale. As a teen, he created his own comic book, The Green Vomit, using spirit duplication, and also co-founded a popular comic book club in St. Louis. Later, he and his brother Charlie made his own amateur three-film series parody of the Republic Pictures Commando Cody serials, using the character name "Commando Cus". The last two of these were made in collaboration with his friend, the late Richard Rosenberg. (Rosenberg had taken over the series with the third, 1973's Commando Cus vs. Kung Fu Killers, in which Gale made a cameo appearance as the title character without his face-covering helmet, and was working on a fourth at the time of his death.)
Gale received a B.A. in Cinema in 1973 from the University of Southern California, where he wrote fanzine reviews for classmate Mike Glyer's fanzine, and met classmate Zemeckis.
As screenwriters, Gale and Zemeckis have collaborated on films including 1941, I Wanna Hold Your Hand, Used Cars, and Trespass, the last set in East St. Louis, Illinois near Gale's home town.
In 1985, both Gale and Zemeckis were nominated for an Academy Award in honor of their screenplay for Back to the Future. In 2002, Gale debuted as a feature-film director with Interstate 60: Episodes of the Road. He had previously directed and wrote the 45-minute theatrical release Mr. Payback: An Interactive Movie.
He also wrote the novelization for his movie 1941 and helped develop the arcade game Tattoo Assassins.
On 31 January 2014, it was announced that a stage musical adaptation of the first Back to the Future film was in production. The show, which is being co-written by original writers Robert Zemeckis and Bob Gale, is expected to be performed in 2015, on the 30th anniversary year of the film. According to Gale, the musical will be "true to the spirit of the film without being a slavish remake".
Gale has also written for comics, including Marvel Comics' Ant-Man's Big Christmas and DC Comics' Batman.
In 2001, Gale had a short run on Marvel Comics' Daredevil, writing issues #20-25 of Volume 2. Working with artists Phil Winslade and David Ross, they created the story arc "Playing to the Camera." Writer-painter David Mack contributed covers to the run.
In 2008 Gale worked as one of the writers among the rotating writer/artist teams on The Amazing Spider-Man, which at the time, was published three times a month. His issues included #546, #552-554, #558, #562-564. He also is the one of the main writers for the IDW relaunch of Back to the Future comics. Which started late in 2015.Kolchak: The Night Stalker (episode "Chopper", with Robert Zemeckis) (1975) (TV)
I Wanna Hold Your Hand (with Robert Zemeckis) (1978)
1941 (with Robert Zemeckis) (1979)
Used Cars (with Robert Zemeckis) (1980)
Back to the Future (with Robert Zemeckis) (1985)
Doctor Strange (Never Filmed) (1986)
Back to the Future Part II (with Robert Zemeckis) (1989)
Back to the Future Part III (with Robert Zemeckis) (1990)
Trespass (with Robert Zemeckis) (1992)
Back to the Future (1991–1992) (TV)
Tales from the Crypt (1993) (TV)
Mr. Payback: An Interactive Movie (1995)
Bordello of Blood (with Robert Zemeckis) (1996) (Story only)
Interstate 60: Episodes of the Road (2002) (also Director)