Snyder was born in Green Bay, Wisconsin, and was raised in Greenwich, Connecticut. His father was an executive recruiter and his mother was a painter and a photography teacher at Daycroft School, which Snyder later attended. Zack attended Camp Owatonna in Harrison, Maine during the summer months as a child. Snyder's mother inspired him to study painting a year after high school at Heatherley School of Fine Art in England, although he had already begun filmmaking. Afterward, Snyder attended the Art Center College of Design in Pasadena, California (where his classmates included Michael Bay and Tarsem Singh). Snyder still lives in Pasadena with his second wife, producer Deborah Snyder, and his six children.

Snyder went on to shoot, as a director and cinematographer, television commercials for such clients as the automobile companies Audi, BMW, Subaru and Nissan, among others. Other commercial work has been for clients including Nike, Reebok, and Gatorade.

Snyder made his feature film debut with the remake Dawn of the Dead (2004), and scored a box office hit with 300 (2007), adapted from writer-artist Frank Miller's Dark Horse Comics miniseries of the same name. His Warner Bros. film Watchmen was released on March 6, 2009; the film made $25,153,000 on its first day. His follow-up project titled Legend of the Guardians has finished filming and is in Post-production. It is due for release in 2010. In the fall of 2010, Zack Snyder is scheduled to start work on a film called Sucker Punch, which is scheduled for release in 2011. The movie is based on an original script, written by Snyder and Steve Shibuya, about an insane young woman in a mental hospital who fantasizes of escape with her fellow inmates.

Snyder often uses slow motion in fight scenes in his films, which Amy Nicholson of Boxoffice magazine remarked separates the director from other filmmakers who make multiple cuts and close-ups during a fight. A minute-long shot from 300 shows King Leonidas walking down as he slaughters his enemies, and the camera only dollys in and out to emphasize each kill.

Snyder's body of work has earned him a number of awards, including two Clio Awards and a Gold Lion Award for his Jeep "Frisbee" commercial. He also won an award for his humorous commercial "General's Party".