After his debut in 1970 with the film Twilight of the Mayas, Lester quickly became a prolific B-movie Director, initially making his mark with a trio of road movies designed for the drive-in market, Steel Arena, Truck Stop Women, and Bobbie Jo and the Outlaw. In 1977, he directed the high-concept thriller Stunts, an early outing for New Line Cinema starring Robert Forster, Joanna Cassidy, and Richard Lynch with a score composed by Michael Kamen. Two years later, he jumped on the disco bandwagon with Roller Boogie starring Linda Blair. The film had a significantly higher budget then his previous films and was the first to be distributed by a major studio. While it received negative reviews upon its initial release, it has since gained cult status as a proverbial time capsule of the bygone Disco Era. to modest success. He then made the exploitation action crime-thriller Class of 1984, a film revolving around a violence in an inner-city school. The Canadian-made production, which featured an early appearance by Michael J. Fox, was controversial at the time of release, but has since gained cult status.

Lester entered the mainstream in 1984 with the Stephen King adaptation Firestarter, and had his biggest hit the following year with Commando, a big-budget Joel Silver-produced Arnold Schwarzenegger action film that grossed over $57 million worldwide. He also directed and produced his sole comedy, Armed and Dangerous starring John Candy, Eugene Levy and Meg Ryan in 1986. In 1990, he directed Class of 1999, a semi-sequel to Class of 1984 starring Malcolm McDowell, Pam Grier, and Stacy Keach. Then in 1991, he directed the cult classic Showdown in Little Tokyo starring Dolph Lundgren and Brandon Lee.

He also founded American World Pictures, an independent production and distribution company. Recent films include The Base, an action film; the thrillers Blowback and Hitman's Run; and for TV, Pterodactyl (produced for the Sci Fi Channel). In 2012, after getting a divorce from Dubovsky, he formed a new distribution company called Titan Global Entertainment.

In January 2013, almost 10 years after directing his last picture, Lester helmed the film Poseidon Rex on location in Belize. The production was disrupted briefly when its lead, Corin Nemec was severely injured during a boating accident while the Belizean Coast Guard was transporting the cast to set. He was replaced by Charmed co-star, Brian Krause.