Robert Petersen, who died Friday at 80, founded Hot Rod magazine in 1947 to publicize a car show, then parlayed it into a magazine empire that included Motor Trend, Skin Diver, and Teen. He also started a business making ammunition, a jet charter company, and a vineyard on a ranch that was Jesse James’s hideout.

A high school dropout who scrabbled his way into Hollywood public relations by planting items in Hedda Hopper’s column, Petersen managed to follow and then lead as California’s car culture swept the nation in the post-World War II years. Soon after founding Hot Rod, he started Motor Trend, a more mainstream publication that catered to buyers of production cars and not just enthusiasts making modifications in their garage.

Petersen became adept at introducing publications to satisfy profitable niches — Rod & Custom, Guns & Ammo, and Sport were all successful titles. As a shaper of young men’s fantasies, Petersen Publishing was rivaled only by Playboy.

Much as Hugh Hefner proved with Playboy, Petersen found that the key to authoritative writing lay in getting involved with the subject matter. He frequently went on safari and once killed a polar bear, armed only with a pistol.

His automotive magazine staff members hung out with race drivers, and Petersen liked to tell stories of racing motorcycles with Steve McQueen. “He’d ride with us all day, then sit around and eat hamburgers and have a few beers,” Petersen told Motor Trend in a 2006 interview. “We had no idea at the time he’d become such a cult figure.”

Perhaps not, but in 2000 Petersen paid more than $1 million for a green 1956 Jaguar XKSS McQueen once drove. The car is one of many formerly owned by stars on display at Petersen Automotive Museum, Petersen’s most lasting contribution to his hometown of Los Angeles.

Petersen was born September 10, 1926, the son of a mechanic for the Los Angeles Department of Water and Power. His mother died when he was young, and Petersen spent a lot of time on the road with father.

“He said, ‘If you’re ever going to be a good mechanic, you need to learn all the parts,'” Petersen recalled in the Motor Trend interview. “So I washed parts, scraped and decarbonized heads, that kind of thing.”

Eventually he got into Hollywood public relations, then served as a reconnaissance photographer in the Army Air Corps during World War II. After the war, he supported himself in part by shooting baby pictures, door to door.

When the National Hot Rod Association hired him to do publicity for a 1947 show, Petersen started Hot Rod, and a year later founded Motor Trend.

The magazines followed Petersen’s passions, with titles including Youth, Outdoor, Photo/ Marine, and Motorcycle/Bicycle. Petersen led the macho life — shooting the guns and driving the cars. He proposed to his wife, a nationally known red-headed model who was Miss Rheingold in 1957, on their first date. The marriage lasted, but tragedy struck in 1975 when their two young sons were killed in a plane crash while on a Colorado skiing vacation.

Petersen Publishing became known for its finely tuned ear for niche marketing (its quarterly Chevy High Performance has a circulation of 120,000) and also for pioneering in computerization. There were failures along the way as well, such as Slot Car Racing, Go Cart, CB Life, and True.

But there were enough successes that in 1996, Petersen sold out to a buyout group led by Willis Stein & Partners for $450 million. The money went into his hugely profitable real estate and jet charter businesses, and a still-growing car collection.

Asked in 2003 which of two spectacularly fast and expensive cars he would rather drive — a Maybach or a Phantom — Petersen answered, “Neither. These are cars you want to be driven in, not drive yourself. As a passenger, I’d pick the Maybach. It’s got more creature comforts in the back seat than any other car today. I especially like the Champagne refrigerator.”