George Wein, the impresario who almost single-handedly turned the jazz festival into a worldwide phenomenon, died on Monday at his apartment in Manhattan. He was 95.

His death was announced by a spokeswoman, Carolyn McClair.

Jazz festivals were not an entirely new idea when Mr. Wein was approached about presenting a weekend of jazz in the open air in Newport, R.I., in 1954. There had been sporadic attempts at such events, notably in both Paris and Nice in 1948. But there had been nothing as ambitious as the festival Mr. Wein staged that July on the grounds of the Newport Casino, an athletic complex near the historic mansions of Bellevue Avenue.

With a lineup including Billie Holiday, Dizzy Gillespie, Oscar Peterson, Ella Fitzgerald and other stars, the inaugural Newport Jazz Festival drew thousands of paying customers over two days and attracted the attention of the news media.It barely broke even; Mr. Wein later recalled that it made a profit of $142.50, and that it ended up in the black only because he waived his $5,000 producer’s fee.

But it was successful enough to merit a return engagement, and before long the Newport festival had established itself as a jazz institution — and as a template for how to present music in the open air on a grand scale.

By the middle 1960s, festivals had become as important as nightclubs and concert halls on the itinerary of virtually every major jazz performer, and Mr. Wein had come to dominate the festival landscape.

He did not have the field to himself: Major events like the Monterey Jazz Festival in California, which began in 1958, and the Montreux Jazz Festival in Switzerland, which began in 1967, were the work of other promoters. But for half a century, if there was a significant jazz festival anywhere in the world, there was a better than even chance it was a George Wein production.

At the height of his success, Mr. Wein was producing events in Warsaw, Paris, Seoul and elsewhere overseas, as well as all over the United States.

Where Jazz History Was Made

Newport remained his flagship, and it quickly became known as a place where jazz history was made. Miles Davis was signed to Columbia Records on the strength of his inspired playing at the 1955 festival. Duke Ellington’s career, which had been in decline, was reinvigorated a year later when his rousing performance at Newport landed him on the cover of Time magazine. The 1958 festival was captured on film by the photographer Bert Stern in the documentary “Jazz on a Summer’s Day,” one of the most celebrated jazz movies ever made.

Mr. Wein’s empire extended beyond jazz. It included the Newport Folk Festival, which played a vital role in the careers of Bob Dylan, Joan Baez and many other performers. (It was at Newport that Mr. Dylan sent shock waves through the folk world by performing with an electric band in 1965.) He also produced the New Orleans Jazz and Heritage Festival, which showcased a broad range of vernacular music as well as the culture and cuisine of New Orleans, and staged festivals devoted to blues, soul, country and even comedy.

His one venture into the world of rock was not a happy experience. Gate-crashers disrupted the 1969 Newport Jazz Festival, whose bill for the first time included rock bands, among them Led Zeppelin and Sly and the Family Stone. The Newport city fathers issued a ban on such acts the next summer; when both rock (the Allman Brothers) and the gate-crashers returned in 1971, Mr. Wein was not invited back. (The Newport Folk Festival, which had not been held in 1970 but was scheduled for later in the summer of 1971, was canceled.)

He was not discouraged. In 1972 he moved the Newport Jazz Festival to New York City, where it became a less bucolic but more grandiose affair, with concerts at Carnegie Hall, Lincoln Center, Radio City Music Hall and other locations around town. Under various names and corporate sponsors, the New York event continued to thrive for almost 40 years. In addition, the jazz festival returned to Newport in 1981 and the folk festival in 1985, both once again under Mr. Wein’s auspices.

Mr. Wein’s success in presenting jazz and folk at Newport helped pave the way for the phenomenon of Woodstock and the profusion of rock festivals in the late 1960s and early ’70s. But jazz was always his first love.

Playing and Promoting

He was a jazz musician before he was a jazz entrepreneur. He began playing piano professionally as a teenager and continued into his 80s, leading small groups, usually billed as the Newport All-Stars, at his festivals and elsewhere. (He performed in public for the first time in several years at Newport in 2019. It was, he announced, “my last performance as a jazz musician.”)

He was a good player, in the relaxed, melodic vein of the great swing pianist Teddy Wilson, with whom he briefly studied. But he determined early on that playing jazz would be a precarious way for him to make a living, and he became more focused on presenting it.

The success of Mr. Wein’s Boston nightclub, Storyville, named after the red-light district of New Orleans where legend has it jazz was born, led Elaine Lorillard, a wealthy Newport resident, to approach him about producing what became the first Newport Jazz Festival, which she and her husband, Louis, financed. And the success of that festival determined the direction his career would take.

George Theodore Wein was born on Oct. 3, 1925, in Lynn, Mass., near Boston, and grew up in the nearby town of Newton. His father, Barnet, was a doctor. His mother, Ruth, was an amateur pianist. Both his parents, he recalled, loved show business and encouraged his interest in music, although they did not necessarily see it as a career option.

Mr. Wein took his first piano lessons at age 8 and discovered jazz while in high school. By the time he entered Northeastern University in Boston, he was beginning to think seriously about a career in jazz.

He served in the Army from 1944 to 1946, spending some time overseas but not seeing combat, and enrolled in Boston University after being discharged. Before graduating with a degree in history in 1950, he was working steadily as a jazz pianist around Boston.

In his autobiography, “Myself Among Others: A Life in Music” (2003), written with Nate Chinen, he said that he knew by then that “music was a crucial part of my being,” but that he also knew that he “had neither the confidence nor the desire to devote my life to being a professional jazz musician.” By the fall of 1950 he was a full-time nightclub owner; by the summer of 1954 he was a festival promoter.

Rough Patches

Mr. Wein encountered some rough times in the early years of the Newport Jazz Festival. In 1960 the bassist Charles Mingus and the drummer Max Roach, protesting what they called Mr. Wein’s overly commercial booking policy, staged a smaller “rebel” festival in another part of Newport in direct competition. But both events were overshadowed when throngs of drunken youths, unable to get tickets to Mr. Wein’s festival, descended on the city, throwing rocks and breaking store windows. City officials shut the Newport Jazz Festival down, although the Mingus-Roach event was allowed to continue.

As a result of the rioting, Mr. Wein’s permit was revoked, and he did not return to Newport in 1961. A festival billed as Music at Newport, staged by another promoter and featuring a range of music including some jazz, was presented in its place but was not successful. Mr. Wein was allowed back the next year, and the festival continued without incident until the end of the decade.

Coverage of Mr. Wein in the jazz press grew more negative over time, and the criticism would persist for the rest of his career. In 1959, the critic Nat Hentoff called the Newport Jazz Festival a “sideshow” that had “nothing to do with the future of jazz.” (Mr. Hentoff later changed his tune: In 2001 he wrote that Mr. Wein had “expanded the audience for jazz more than any other promoter in the music’s history.”)

Mr. Wein was sometimes attacked as exploitive, money-hungry, unimaginative in his programming and too willing to present non-jazz artists at his jazz festivals — criticism first heard when he booked Chuck Berry at Newport in 1958, and heard again when he booked the likes of Ray Charles, Frank Sinatra and even the folk group the Kingston Trio (who performed at both the folk and jazz festivals in 1959). He professed to take the criticism in stride, but in his autobiography he left no doubt that he had forgotten none of it, quoting many of his worst notices and patiently explaining why they were wrong.

The two Newport festivals had been established as nonprofit ventures, but in 1960 Mr. Wein formed a corporation, Festival Productions, to run what soon became a worldwide empire. At the company’s height it was producing festivals and tours in some 50 cities worldwide. Over the years he also tried his hand at personal management and record production.

After years of, by his account, struggling to break even, Mr. Wein became a pioneer in corporate sponsorship in the late 1960s and ’70s, enlisting beer, tobacco and audio equipment companies to underwrite his festivals and tours. There was the Schlitz Salute to Jazz, the Kool Jazz Festival and, most enduringly, a partnership with the Japanese electronics giant JVC, which began in 1984 and lasted until 2008.

“I never realized that you could make money until sponsors came along,” he told The New York Times in 2004. “The credibility we’d been working on all those years always brought media notice. And then the opportunity for media notice was picked up by sponsors.”

In 1959, Mr. Wein married Joyce Alexander, who worked alongside him as a vice president of Festival Productions for four decades. She died in 2005. No immediate family members survive.

Presidential Honors

Over the years Mr. Wein received numerous honors and accolades. He was named a National Endowment for the Arts Jazz Master in 2005 and inducted into the French Legion of Honor in 1991. He was honored by two presidents, Jimmy Carter in 1978 and Bill Clinton in 1993, at all-star White House jazz concerts celebrating the anniversary of the first Newport Jazz Festival. In 2015, the Recording Academy gave him a Trustees Award for lifetime achievement.

In 2007, nine years after a deal to sell 80 percent of Festival Productions to Black Entertainment Television fell through, the company was acquired by a newly formed company, the Festival Network. Mr. Wein remained involved, but as an employee — a kind of producer emeritus — and not the boss.

Things changed again in 2009, when the Festival Network ran into financial problems and Mr. Wein regained control of the handful of festivals left in what had once been a vast empire. (At first he was legally prevented from using the names Newport Jazz Festival and Newport Folk Festival because they belonged to the Festival Network, but he reacquired the rights in 2010.)

He also found new sponsors for the Newport Jazz Festival — first a medical equipment company and later an asset management firm, Natixis — to replace his longtime corporate partner, JVC. The folk festival, whose sponsors in recent years had included Ben & Jerry’s and Dunkin’ Donuts, had by then been without sponsorship for several years; both festivals were later partly sponsored by the jewelry company Alex and Ani.

In 2011 Mr. Wein announced that both Newport festivals, the only events he was still producing, would become part of a new nonprofit organization, the Newport Festivals Foundation.

He eventually handed over the reins of both festivals, although he remained involved until the end. Jay Sweet became producer of the folk festival in 2009 and six years later was named executive producer of the Newport Festivals Foundation. In 2016 Danny Melnick was promoted from associate producer to producer of the jazz festival, and the jazz bassist and bandleader Christian McBride, who had performed at Newport numerous times since 1991, was named artistic director.

The coronavirus pandemic caused the cancellation of both festivals in 2020, but they were back the next year. Mr. Wein had planned to attend the 2021 jazz festival, but on July 28, just two days before it was scheduled to begin, he announced on social media that he would not be there. (He did participate remotely, introducing the singers Mavis Staples, by phone, and Andra Day, via FaceTime.)

“At my age of 95, making the trip will be too difficult for me,” he wrote. “I am heartbroken to miss seeing all my friends.” But, he added, with a new team in place to run both festivals, “I can see that my legacy is in good hands.”