Producer Milton Okun, known for bringing classical arrangements to folk-pop songs and for co-founding Cherry Lane Music, died Tuesday in Los Angeles. He was 92.

His most-celebrated work in the 1960s, when folk music entered the mainstream, was his arrangements for Peter, Paul & Mary. He worked with many folk groups and musicians at the time—Harry Belafonte, Odetta, Tom Paxton, Laura Nyro, the Chad Mitchell Trio—and in the 1970s, he worked steadily with John Denver, producing and handling arrangements on all his RCA albums.

Okun’s belief that classical and folk could work together led to the 1981 Denver-Placido Domingo collaboration Perhaps Love. The relationship with Domingo—he continued to produce his English-language albums—brought him back to his beloved classical music.

A founding member and major supporter of the Los Angeles Opera, Okun was pivotal in bringing Domingo to L.A. Opera as the Artistic Director.

A Brooklyn native who was a child-prodigy pianist, he suffered nephritis in his early teens and after two years of bed rest, he could no longer play. He studied music and conducting at Oberlin, and after graduating became a music teacher in the New York public school system.

But his love of folk music drew him into singing, arranging, and conducting, first with Belafonte, which led him to acts such The Brothers Four and Peter Paul and Mary. One of his productions for Peter, Paul & Mary was on Denver’s “Leaving on a Jet Plane,” which led to Okun working with the singer after he left the Chad Mitchell Trio, another Okun client.

During this successful run, Okun and his wife Rosemary were growing Cherry Lane Music, which they started in 1960, into one of the largest independent music publishers.

As producer and arranger, Okun collected more than 75 gold and platinum records and 16 Grammy nominations. And his love for opera and Denver’s music never waned: At the age of 89, he produced Great Voices Sing John Denver, a collection of opera singers interpreting Denver’s songs.