SAN FRANCISCO — Larry Gordon, who helped turn surfing into a mainstream sport with the foam boards he created at his California company, died Saturday. He was 76.

Mr. Gordon’s wife, Gayle, said he died peacefully on New Year’s Day at his San Diego home after a lengthy illness. He was diagnosed with Parkinson’s disease 10 years ago.

“Very few people get to have a business and a life in their passion,’’ his wife said. “He got to live a life in the sport that gave him great joy.’’

Mr. Gordon was a chemistry student at San Diego State University in the late 1950s when he started experimenting with foam materials at his father’s plastics factory and shaping boards in his friend Floyd Smith’s garage.

At the time, surfboards were mostly made of balsa wood and were heavy and hard to maneuver. The polyurethane foam that Mr. Gordon and Smith used to build their boards was lighter and easier to ride, making surfing more accessible and helping drive its popularity across the globe.

Demand for the boards led the pair to move out of the garage in Pacific Beach and open a full-fledged surf shop in 1959.

By the 1960s, Gordon & Smith Surfboards became a leading manufacturer in the surf industry, later branching out into skateboards and surf wear.

Smith sold his share of the company in 1971 after expanding the line into Australia. Gordon & Smith is now run by Mr. Gordon’s oldest daughter, Debbie Gordon.

“We still shape and glass surfboards about a mile from where his first factory was,’’ his daughter said.