He created many series, including Alias Smith and Jones, Battlestar Galactica, Buck Rogers in the 25th Century, The Misadventures of Sheriff Lobo, Quincy, M.E., The Hardy Boys/Nancy Drew Mysteries, B. J. and the Bear, The Fall Guy, Magnum, P.I., and Knight Rider.

The Four Preps ultimately produced three gold records for Capitol, all of which Larson himself wrote and/or composed: "26 Miles (Santa Catalina)", "Big Man", and "Down by the Station".

A later member of the Four Preps, David Somerville, and a session singer he knew, Gail Jensen, later collaborated with Larson to write and compose "The Unknown Stuntman", the theme from The Fall Guy; series lead Lee Majors performed this song over the opening titles.

His first hit series was Alias Smith and Jones, a 1971–1973 Western which described the activities of Hannibal Heyes and Jedediah "Kid" Curry, concentrating on their efforts to go straight.

(George Roy Hill's film, scripted by William Goldman, about Butch Cassidy and the "Sundance Kid", is commonly believed to have been the inspiration for the series.

)[1] Larson was involved in the development for television of The Six Million Dollar Man, based on Martin Caidin's novel Cyborg, into the successful series, and was one of the program's early executive producers.

Larson, a member of the Church of Jesus Christ of Latter-day Saints in real life,[2][3] had been working on the concept since 1968 with former Star Trek producer Gene L. Coon mentoring him in its early development.

Despite his success, much criticism has been aimed at Larson for his perceived general lack of originality as many of his television series are seen as small screen "knock-offs" of feature films.

Larson's involvement with Universal had begun in the 1970s, and his contractual agreement had secured him net profits from the revenues generated by the shows he worked on as a producer, including The Six Million Dollar Man, Quincy, M.E., Battlestar Galactica, Buck Rogers in the 25th Century, Magnum, P.I.

Larson died on November 14, 2014, in UCLA Medical Center, Santa Monica, California, from esophageal cancer, aged 77 and was survived by his wife Jeannie and nine children.