Harvey Lavan Cliburn Jr., an American pianist of extraordinary gifts who set off seismic waves in the political landscape by winning the 1958 Tchaikovsky Piano Competition in Moscow at the height of the Cold War, has passed away at the age of 78. The cause was bone cancer. Cliburn, known among friends and admirers as "Van," died in his home in Fort Worth, Texas, where an international piano competition in his name celebrated its 50th anniversary last fall.

Van Cliburn, left, being congratulated by Nikita Khrushchev in 1958. Associated Press

That competition, one of the most important in the world, is perhaps the most visible part of his legacy for today's generation of music lovers. However, few alive in 1958 could forget the dramatic impact of that Moscow event.

America was in the throes of a national state of anxiety over the Soviet Union's launch of its Sputnik space satellites. The Tchaikovsky Competition, designed to elevate the Communist nation even higher by proving Russian superiority in art as well as in science, featured a jury heavily weighted with Soviet musical greats, including pianists Sviatoslav Richter and Emil Gilels, and composers Dmitri Kabalevsky and Aram Khachaturian. A Russian was supposed to win.

But when the 23-year-old American from Texas played Tchaikovsky and Rachmaninoff with soul-rending mastery, the audience—already charmed by Mr. Cliburn's warmth and homespun manner in his public appearances—went wild. It became impossible to award first place to anyone else; the jury, equally spellbound by his artistry, requested permission to give him the prize, and Soviet Premier Nikita Khrushchev granted official consent.

In that moment, political normality was shattered. Yet, in a sense, the stars had been aligned for just this outcome. There was already tremendous curiosity about the West, especially on the part of Soviet youth, voracious for movies (particularly Tarzan and westerns), music (rock and jazz, even though they were banned) and other aspects of American life. The post-Stalin years had emboldened many of the jury members, who seemed to celebrate the American's win as a small victory of their own against the political establishment. And then there was the Cliburn style—a luscious "magnolia blossom" sound (in the words of one Texas patron), infused with a kind of grand Romantic passion that had been all but drained out of students in the conformist programs of Soviet schools. Cliburn's pianism conveyed, above all, a sublime sense of expressive freedom. For some Soviet listeners, it represented democracy itself.

The Soviets tried to save face by noting that his Juilliard teacher, Rosina Lhévinne —his principal mentor after childhood lessons with his mother Rildia Bee, and a graduate of the Moscow Conservatory—was an exemplar of their tradition. But in internal documents released after the collapse of the Soviet Union, political and musical authorities expressed consternation and disappointment with the outcome of their own conservatory training programs.

Back in America, the conquering hero—now known as the "American Sputnik"—was given a tickertape parade down New York's Broadway. He became the first classical musician ever to have a million-selling record. He performed in stadiums—and nearly everywhere the crowds demanded the Tchaikovsky First Piano Concerto, one of his winning vehicles in Moscow. Cliburn had succeeded in previous competitions, notably the prestigious Leventritt, whose winners had included Eugene Istomin, Alexis Weissenberg and Gary Graffman. But nothing had prepared him for this.

Suddenly, he was eclipsing the greatest names in music. When he joined with Igor Stravinsky at the 1962 World's Fair in Seattle—the pianist, in typical fashion, insisted on carrying the composer's heavy bags to their backstage dressing rooms—Cliburn performed Rachmaninoff's Third Piano Concerto to a packed house on the first half of the program. After intermission, the greatest composer of the 20th century took to the stage to conduct his masterpiece, "The Firebird." The hall was half empty.

"I'm not a success," Cliburn announced with stunning foresight after winning in Moscow. "I'm just a sensation." Yet this pianist, who readily admitted he did not like to practice, became a slave to his celebrity. Some advisers—including conductor Kirill Kondrashin, with whom he had achieved such heights at the competition and with his concerto recording—warned that he should curtail his appearances to study, practice and learn new repertoire. That wasn't in the cards.

As the years passed, the critics found that his sound—described by fellow Juilliard classmate Jeaneane Dowis as so natural it seemed to come "from the birds and the bees and the trees and the air"—had begun to lose its luster, and his interpretations some of their artfulness. His eccentricities—on the public stage, Cliburn could veer toward affected grandiosity or oversaturated sentimentality—now seemed to capture more attention than the playing. Starting in 1975, he began to think about withdrawing from the concert scene; three years later he did. The resumption of that career after a 12-year break turned out to be half-hearted—he even limited the number of engagements by demanding outlandish fees.

Yet the achievements over his lifetime were considerable. His name is still magical in Russia, which became a second home to which he returned often. His win invigorated fledgling efforts at cultural exchange. Many of his recordings are things of rare beauty, and his example stood as an inspiration to countless young pianists. The competition in Fort Worth spurred by his success has given emerging piano hopefuls a world-wide platform.

That's not a bad legacy. In the end, what more could we really have asked for?

Mr. Isacoff is at work on a book about the 1958 Tchaikovsky Piano Competition.