Zaentz, 92, suffered from Alzheimer's disease, Variety reported. His nephew and colleague, Paul Zaentz, called him "an extraordinary person."
A native of Passaic, N.J., Zaentz got into the music business after military service in World War II. He worked for Norman Granz, a jazz producer and promoter in San Francisco, and for Fantasy Records, a label that produced Dave Brubeck, Mort Sahl, Lenny Bruce and, later on, the rock group Creedence Clearwater Revival.
Zaentz, often litigious, was involved in several lawsuits with Creedence frontman Tom Fogerty.
In 1968, Zaentz optioned two novels, "One Flew Over the Cuckoo's Nest" by Ken Kesey and "At Play in the Fields of the Lord" by Peter Matthiessen. "One Flew Over the Cuckoo's Nest" was awarded the 1975 Best Picture Oscar and its stars, Jack Nicholson and Louise Fletcher, and director, Milos Forman, also won.
Zaentz's other Oscar-winners were "Amadeus" in 1984 and "The English Patient" in 1995. The night he was honored for "The English Patient" he also received the Irving Thalberg Award.
Another author Zaentz optioned was J.R.R. Tolkien. He produced Ralph Bakshi's 1978 animated "Lord of the Rings," a critical and commercial failure that covered only the first half of the trilogy.
The live-action "Lord of the Rings" movies directed by Peter Jackson were made by New Line Cinema. Zaentz took New Line to court, saying he was being shortchanged on his share of the profits.