The cause was lung cancer, said Diane Fehring Reynolds, a friend.

"If there were such a thing, Greene would hold the Jelly Roll Morton Chair of Music at an Ivy League college," Whitney Balliett, The New Yorker's longtime jazz critic, wrote in The Atlantic in 1998.

Such was Mr. Greene's devotion to Morton, a swaggering, seminal figure in jazz — pianist, bandleader and "the first important jazz composer," according to The New Grove Dictionary of Jazz — that he viewed his task as not simply to play Morton's music also but to recreate it, performing and recording the music as Morton himself did.

"He gets inside Morton's music," Mr. Balliett wrote.

Morton was born in the late 19th century in New Orleans and grew up in the city's distinctive musical atmosphere. In his playing and writing he drew from it, fusing ragtime, the blues, spirituals and Latin music from the Caribbean into songs that were contained by compositional form and yet exuded an earthy drive.

In the late 1920s he put together a band known as the Red Hot Peppers and recorded songs with them that melded composition and improvisation, with each of the brass, woodwind and rhythm players getting to show his stuff within the framework of Morton's writing.

Through the 1970s and '80s, Mr. Greene toured the country and the world as a Jelly Roll evangelist, bringing Morton's music to France, Denmark, England and Japan, both as a solo pianist and as a bandleader. He can be heard playing Morton's music on the soundtrack of Louis Malle's 1978 film, "Pretty Baby," about a girl — Brooke Shields in her first role — raised in a New Orleans brothel, circa 1917. "There's such a vitality to his music," Mr. Greene told the online arts magazine Joyzine. "Yet it's not wild — it's contained by the forms in which Jelly wrote: the limited harmonies, the very formal three-part structure of his songs, the fact that each song could only last about three minutes." He added, "It can get very hot, yet it never explodes because it's locked into these restrictions. Within these imposed boundaries, it's almost Mozartean in its magnificence."

Mr. Greene was introduced to Morton's music in the 1940s — Morton died in 1941 — and though he was a serious, self-taught amateur musician, he never planned to be a professional. Rather, he made a living writing documentaries for radio and television. But as he told the story, his career pivoted in June 1968; he was about to join Robert F. Kennedy's campaign for the presidency when Kennedy was assassinated.

"When Bobby got shot, I realized that the time had come for me to get into music full time," he told Joyzine. "Certainly if he had lived I wouldn't have devoted myself to Jelly the way that I have."

By 1969 he was playing recitals of Morton's music in New Orleans. In 1973 he introduced his own version of the Red Hot Peppers at Lincoln Center as part of the Newport Jazz Festival in New York. The next year the band returned to Lincoln Center, where, John S. Wilson wrote in The New York Times, it "not only played 'those little black dots,' as Mr. Morton always instructed his musicians, but projected the flavor of Mr. Morton's music — the breaks, the slurs, the accents, the coloring."

Robert Stern Greenstein was born on Sept. 4, 1922, to Oscar Greenstein, who ran a textile concern, and the former Elsa Stern, and grew up on the Upper East Side of Manhattan. His father's business foundered after the stock market crash in 1929, and the family's circumstances were considerably reduced for a time, but Mr. Greenstein remade his fortune with a company that made name tags. The father changed the family name sometime after 1939, Ms. Reynolds said.

Mr. Greene graduated from Columbia in 1943 and began writing documentaries for radio and then television, winning Writers Guild awards in 1957 and 1962 for history-based radio scripts. In 1964, writing for Voice of America, the federal government's broadcast network, he was nominated again. Mr. Greene taught from 1954 to 1962 in the dramatic arts department at Columbia, where he earned a Master of Fine Arts degree in theater arts in 1958. He leaves no immediate survivors.

"If it was once done so perfectly, why do it again?" Mr. Greene once asked aloud, voicing perhaps the most obvious question about his devotion to Jelly Roll Morton. "I can only say: Because there's beauty there, there's excitement, there's love. If that can be transmitted to a live audience, some of the aroma of the original happens again."