Van Cliburn, the American pianist whose first-place award at the 1958 International Tchaikovsky Competition in Moscow made him an overnight sensation and propelled him to a phenomenally successful and lucrative career, though a short-lived one, died on Wednesday at his home in Fort Worth. He was 78.

His publicist, Mary Lou Falcone, confirmed the death, saying that Mr. Cliburn had been treated for bone cancer.

Hailing from Texas, Mr. Cliburn was a tall, lanky 23-year-old when he clinched the gold medal in the inaugural year of the Tchaikovsky competition. The feat, in Moscow, was viewed as an American triumph over the Soviet Union at the height of the cold war. He became a cultural celebrity of pop-star dimensions and brought overdue attention to the musical assets of his native land.

When Mr. Cliburn returned to New York he received a ticker-tape parade in Lower Manhattan, the first musician to be so honored, cheered by 100,000 people lining Broadway. In a ceremony at City Hall, Mayor Robert F. Wagner proclaimed that “with his two hands, Van Cliburn struck a chord which has resounded around the world, raising our prestige with artists and music lovers everywhere.”

Even before his Moscow victory the Juilliard-trained Mr. Cliburn was a notable up-and-coming pianist. He won the Leventritt Foundation award in 1954, which earned him debuts with five major orchestras, including the New York Philharmonic under Dimitri Mitropoulos. For that performance, at Carnegie Hall in November 1954, he performed the work that would become his signature piece, Tchaikovsky’s Piano Concerto No. 1, garnering enthusiastic reviews and a contract with Columbia Artists.

At the time, Mr. Cliburn was part of an exceptional American generation of pianists in promising stages of their own careers, among them Leon Fleisher, Byron Janis and Gary Graffman. And the Tchaikovsky competition came at a time when American morale had been shaken in 1957 by the Soviet Union’s launching of Sputnik, the world’s first artificial satellite.

The impact of Mr. Cliburn’s victory was enhanced by a series of vivid articles written for The New York Times by Max Frankel, then a foreign correspondent based in Moscow and later an executive editor of the paper. The reports of Mr. Cliburn’s progress — prevailing during the early rounds, making it to the finals and becoming the darling of the Russian people, who embraced him in the streets and flooded him with fan mail and flowers — created intense anticipation as he entered the finals.

In his 1999 memoir, “The Times of My Life and My Life With The Times,” Mr. Frankel recalled his coverage of Mr. Cliburn’s triumph in Moscow: “The Soviet public celebrated Cliburn not only for his artistry but for his nationality; affection for him was a safe expression of affection for America.”

Mr. Frankel said he had “posed the obvious question of whether the Soviet authorities would let an American beat out the finest Russian contestants.”

“We now know that Khrushchev” — Nikita S. Khrushchev, the Soviet premier — “personally approved Cliburn’s victory,” he wrote, “making Van a hero at home and a symbol of a new maturity in relations between the two societies.”

Mr. Cliburn was at first oblivious to the political ramifications of the prize.

“Oh, I never thought about all that,” Mr. Cliburn recalled in 2008 during an interview with The Times. “I was just so involved with the sweet and friendly people who were so passionate about music.” The Russians, he added, “reminded me of Texans.”

The interview was conducted in conjunction with 50th-anniversary celebrations of the Moscow competition. The festivities, sponsored by the Van Cliburn Foundation, included a gala dinner at the Kimbell Art Museum in Fort Worth for 1,000 guests, among them the Russian culture minister and the Russian ambassador to the United States, who led a long round of toasts.

Mr. Cliburn was a naturally gifted pianist whose enormous hands had an uncommonly wide span. He developed a commanding technique, cultivated an exceptionally warm tone and manifested deep musical sensitivity. At its best his playing had a surging Romantic fervor, but one leavened by an unsentimental restraint that seemed peculiarly American. The towering Russian pianist Sviatoslav Richter, a juror for the competition, described Mr. Cliburn as a genius — a word, he added, “I do not use lightly about performers.”

Drawbacks of Early Success

But if the Tchaikovsky competition represented Mr. Cliburn’s breakthrough, it also turned out to be his undoing. Relying inordinately on his keen musical instincts, he was not an especially probing artist, and his growth was stalled by his early success. Audiences everywhere wanted to hear him in his prizewinning pieces, the Tchaikovsky First Concerto and the Rachmaninoff Third. Every American town with a community concert series wanted him to come play a recital.

“When I won the Tchaikovsky I was only 23, and everyone talked about that,” Mr. Cliburn said in 2008. “But I felt like I had been at this thing for 20 years already. It was thrilling to be wanted. But it was pressure, too.”

His subsequent explorations of wider repertory grew increasingly insecure. During the 1960s he played less and less. By 1978 he had retired from the stage; he returned in 1989, but performed rarely. Ultimately, his promise and potential were never fulfilled, but his great talent was apparent early on.

Harvey Lavan Cliburn Jr. was born in Shreveport, La., on July 12, 1934. His mother, Rildia Bee O’Bryan, a pianist who had studied in New York with Arthur Friedheim, a longtime student of Liszt, had hoped to have a career in music, but her mother forbade it. Instead she married Harvey Lavan Cliburn, a purchasing agent for an oil company, a laconic man of moderate income.

An only child, Van started studying with his mother when he was 3. By 4 he was playing in student recitals. When he was 6 the family moved to Kilgore, Tex. (population 10,500). Although Van’s father had hoped his son would become a medical missionary, he realized that the boy was destined for music, so he added a practice studio to the garage.

As a plump 13-year-old Mr. Cliburn won a statewide competition to perform with the Houston Symphony and he played the Tchaikovsky concerto. Thinking her son should study with a more well-connected and advanced teacher, Mr. Cliburn’s mother took him to New York, where he attended master classes at Juilliard and was offered a scholarship to the school’s preparatory division. But Van adamantly refused to study with anyone but his mother, so they returned to Kilgore.

He spoke with affecting respect for his mother’s excellence as a teacher and attributed the lyrical elegance of his playing to her. “My mother had a gorgeous singing voice,” he said. “She always told me that the first instrument is the human voice. When you are playing the piano, it is not digital. You must find a singing sound — the ‘eye of the sound,’ she called it.”

By 16 he had shot up to 6 feet 4 inches. Excruciatingly self-conscious, he was excused from athletics out of fear that he might injure his hands. He later recalled his adolescence outside the family as “a living hell.”

On graduation at 17 he finally accepted a scholarship from Juilliard and moved to New York. Studying with the Russian-born piano pedagogue Rosina Lhevinne, he entered the diploma rather than the degree program to spare himself from having to take 60 semester hours of academic credits. Even his close friends said he displayed little intellectual curiosity outside of music.

Winning the Leventritt award in 1954 was a major achievement. Though held annually, the competition had not given a prize in three years because the judges had not deemed any contestant worthy. But this panel, which included Rudolf Serkin, George Szell and Leonard Bernstein, was united in its assessment of Mr. Cliburn.

That same year he graduated from Juilliard and was to have begun graduate-level studies. But performing commitments as a result of the Leventritt kept him on tour.

In 1957 he was inducted into the Army but released after two days because he was found to be prone to nosebleeds. By this point, despite his success, his career was stagnating and he was $7,000 in debt. His managers at Columbia Artists wanted him to undertake a European tour. But Ms. Lhevinne encouraged him instead to enter the first Tchaikovsky competition.

A $1,000 grant from the Martha Baird Rockefeller Aid to Music program made the journey to the Soviet Union possible. The contestants’ Moscow expenses were paid by the Soviet government.

A Darling of the Russians

The Russian people warmed to Mr. Cliburn from the preliminary rounds. There was something endearing about the contrast between his gawky boyishness and his complete absorption while performing. At the piano he bent far back from the keys, staring into space, his head tilted in a kind of pained ecstasy. During rapid-fire passages he would lean in close, almost scowling at his fingers. On the night of the final round, when Mr. Cliburn performed the Tchaikovsky First Concerto, a solo work by Dmitry Kabalevsky (written as a test piece for the competition) and the Rachmaninoff Third Concerto, the audience broke into chants of “First prize! First prize!” Emil Gilels, one of the judges, went backstage to embrace him.

The jury agreed with the public, and Moscow celebrated. At a Kremlin reception, Mr. Cliburn was bearhugged by Khrushchev. “Why are you so tall?” Khrushchev asked. “Because I am from Texas,” Mr. Cliburn answered.

His prize consisted of 25,000 rubles (about $2,500), though he was permitted to take only half of that out of the country. Immediately, concert offers for enormous fees engulfed him.

His income for the 1958-59 concert season topped $150,000. His postcompetition concert at Carnegie Hall on May 19, 1958, with Kiril Kondrashin and the Symphony of the Air, repeating the program from the final round, was broadcast over WQXR. He signed a contract with RCA Victor, and his recording of the Tchaikovsky First Concerto sold over a million copies within a year.

Reviewing that recording in The Times in 1958, the critic Harold C. Schonberg wrote, “Cliburn stands revealed as a pianist whose potentialities have fused into a combination of uncommon virtuosity and musicianship.” Yet Mr. Schonberg had reservations even then: “If there is one thing lacking in this performance it is the final touch of flexibility that can come only with years of public experience.”

An idolatrous biography, “The Van Cliburn Legend,” written by the pianist and composer Abram Chasins, with Villa Stiles, was published in 1959. Mr. Chasins used Mr. Cliburn’s Moscow victory as a club to attack the American cultural system for neglecting its own.

Nothing could diminish Mr. Cliburn’s popularity in the late 1950s. He earned a then-stunning $5,000 for a pair of concerts at the Hollywood Bowl, and played with the Moscow State Symphony at Madison Square Garden for an audience of over 16,000.

Yet as early as 1959 his attempts to broaden his repertory were not well received. That year, for a New York Philharmonic benefit concert at Carnegie Hall conducted by Bernstein, Mr. Cliburn played the Mozart Piano Concerto No. 25, the Schumann Concerto and the Prokofiev Third Concerto. Howard Taubman, reviewing the program in The Times, called the Mozart performance “almost a total disappointment.” Only the Prokofiev was successful, he wrote, praising the brashness, exuberance and crispness of the playing.

Reviewing a 1961 performance of Beethoven’s “Emperor” Concerto by Mr. Cliburn with the Philadelphia Orchestra under Eugene Ormandy, Mr. Schonberg wrote, “It was the playing of an old-young man, but without the spirit of youth or the mellowness of age.” Mr. Cliburn performed the Rachmaninoff Third Concerto yet again, with the Philadelphia Orchestra, for the inaugural week of Philharmonic Hall (now Avery Fisher Hall) in 1962.

Despite the criticism, Mr. Cliburn tried to expand his repertory, playing concertos by MacDowell and Prokofiev and solo works by Samuel Barber (the demanding Piano Sonata), Chopin, Brahms, Beethoven and Liszt. But the artistic growth and maturity that were expected of him never fully came. Even as a personality, Mr. Cliburn began to seem out of step. In the late 1950s this baby-faced, teetotaling, churchgoing, wholesome Texan had fit the times. But to young Americans of the late 1960s he seemed a strained, stiff representative of the demonized establishment.

A New Competition

Many subsequent pianists tried to emulate Mr. Cliburn’s path to success through international competition victories. But a significant number of critics and teachers took to castigating the premise and value of competitions as an encouragement of faceless virtuosity, superficial brilliance and inoffensive interpretations. Nevertheless, in 1962, some arts patrons and business leaders in the Fort Worth area, to honor their hometown hero, inaugurated the Van Cliburn International Piano Competition. It remains the most lucrative and visible of these contests.

In 1978, at 44, Mr. Cliburn, now a wealthy man, announced his withdrawal from concertizing. He moved with his mother into a magnificent home in the Fort Worth area, where he hosted frequent late-night dinner parties.

As a young man Mr. Cliburn was briefly linked romantically with a soprano classmate from Juilliard. But even then he was discreet in his homosexuality. That discretion was relaxed considerably in 1966 when, at 32, he met Thomas E. Zaremba, who was 19.

The details of their romantic relationship exploded into public view in 1996, when Mr. Zaremba filed a palimony suit against Mr. Cliburn seeking “multiple millions,” according to The Fort Worth Star-Telegram. Mr. Zaremba, who had moved to Michigan and become a funeral director, claimed that during his 17-year relationship with Mr. Cliburn he had served as a business associate and promoter and that he had helped care for Mr. Cliburn’s mother, who died in 1994 at 97. The suit was eventually dismissed.

Mr. Cliburn returned to the concert stage in 1987, but his following performances were infrequent. The stress involved was almost palpable on May 21, 1998, when, to inaugurate a concert hall in Fort Worth, Mr. Cliburn played the Rachmaninoff Second Concerto with the Fort Worth Symphony, suffered a memory lapse in the final movement and collapsed onstage. He was given oxygen by a medical team backstage and taken to a hospital.

“It was a massive panic attack,” a friend, John Ardoin, who was a critic at The Dallas Morning News, said at the time. “It was sheer exhaustion and nervousness. Van had given a solo recital two days earlier, a really first-class performance, a black-tie affair with all of the cultural and political officialdom of Texas in attendance, and he was overwhelmed by it all.”

His last public appearance was in September, when he spoke at a concert, at Bass Performance Hall in Fort Worth, celebrating the 50th anniversary of the Van Cliburn Foundation. He is survived by Thomas L. Smith, with whom he shared his home for many years.

Mr. Cliburn leaves a lasting if not extensive discography. One recording in particular, his performance of the Rachmaninoff Third Concerto recorded live at Carnegie Hall on the night of his post-Tchaikovsky competition concert, was praised by Mr. Schonberg, the critic, for its technical strength, musical poise, and “manly lyricism unmarred by eccentricity.”

Mr. Schonberg then added, prophetically, “No matter what Cliburn eventually goes on to do this will be one of the great spots of his career; and if for some reason he fails to fulfill his potentialities, he will always have this to look back upon.”