Raymond Gniewek, the concertmaster for the Metropolitan Opera Orchestra for 43 years anda quiet but vital force in elevating that ensemble to a new level of renown, died on Oct. 1 in Naples, Fla. He was 89.

His daughter Susan Law said the cause was complications of cancer.

Mr. Gniewek (pronounced NYEH-vik), a violinist whose solos invariably drew acclaim, was just 25 in 1957 when he was named the orchestra’s concertmaster. He had two obstacles to overcome.

In a genre, opera, with a heavily European heritage, he was only the second American-born musician to hold the job at the Met. And he was the youngest member of the orchestra when he was made concertmaster, whose duties include advising musicians with much more tenure and experience.

He managed to make it work.

“I sort of waded my way through things, wasn’t too arrogant, and the musicians were very supportive,” he told The New York Times in 2000 in an interview occasioned by his retirement.

The concertmaster, the leader of the violin section, is most visible in tuning up the orchestra before a concert, but is more crucially a conduit between the conductor and the rest of the players, helping to bring about the interpretation the conductor wants. That often means mastering a particular passage or effect, then demonstrating to fellow violinists the bowing technique or fingering needed to achieve it.

“It’s my job to make technical translations of the desired sound,” Mr. Gniewek said in the 2000 interview. “And you have to show, not tell, because the same words can mean different things to different people.”

Another part of the job is to ensure stability and continuity, especially important in an orchestra like the Met Opera’s that is often led by guest conductors. As the Berklee College of Music describes the job on its careers page, “While conductors may come and go — with differing styles and approaches — the concertmaster provides the orchestra with consistent and technically oriented leadership.”

Mr. Gniewek found that being concertmaster could mean being an alarm clock. There is Met lore about a German conductor who would fall asleep during the dialogue of Carl Maria von Weber’s “Der Freischütz”; Mr. Gniewek would awaken him with a subtle, “Jetzt, maestro” (“Now, maestro”).

Mr. Gniewek was credited with helping to raise the ensemble’s game considerably. When he was first named to the post, the orchestra was workmanlike at best. By the early 1990s it was playing concerts, making acclaimed recordings and being compared to the world’s great orchestras.

“It plays with astonishing precision, nuance and insight,” Katrine Ames wrote of the Met Orchestra in Newsweek in 1991, adding, “Fifteen years ago that orchestra was little more than adequate: it gave some fine performances (usually Verdi) and some dismal ones (usually Mozart). To hear it was largely to ignore it.”

Much of that improvement was credited to James Levine, who became the Met’s principal conductor in the 1973-74 season and was soon named its music director. But insiders knew that Mr. Gniewek was vital to executing Mr. Levine’s vision, something Mr. Levine himself acknowledged when Mr. Gniewek retired.

“The single luckiest thing to happen to me since I have been at the Met,” he said, “is that Ray Gniewek was the concertmaster.”

Raymond Arthur Gniewek was born on Nov. 13, 1931, in East Meadow, N.Y., on Long Island. His father, Jacenta, was a tradesman and barber who also played violin, and his mother, Leocadia (Kurowska) Gniewek, was a church organist and homemaker.

After graduating from Hempstead High School, he attended the Eastman School of Music in Rochester, N.Y., becoming a member of the Rochester Philharmonic Orchestra while an undergraduate. He graduated in 1953. In 1955, he was named concertmaster of the Rochester Civic Orchestra and assistant concertmaster of the Rochester Philharmonic.

He had been Met concertmaster for almost a decade — and for some 1,700 performances — when he made his New York City recital debut in 1966 at Town Hall. Richard D. Freed, reviewing that performance in The Times, could barely contain his enthusiasm.

“Mr. Gniewek has everything that could be wanted in a violinist — impeccable intonation, a technique so secure that he is free to concentrate on problems of interpretation and a pronounced flair for particular style,” he wrote.

Early in his tenure, in 1958, Mr. Gniewek had to take the baton when the conductor Fausto Cleva fell ill during a performance of “Manon Lescaut.” That might have been a fantasy fulfilled for some concertmasters with conducting aspirations, but not for Mr. Gniewek.

“I’d rather play,” he told The Times in the 2000 interview. “I have strong feelings about sound, the actual act of playing of the instrument. It’s what I do best.”

Mr. Gniewek moved to Florida after retiring and lived in Naples at his death. His first marriage, to Doris Scott in the 1950s, ended in divorce, as did his marriage in 1960 to Lolita San Miguel. In addition to his daughter, who is from his first marriage, he is survived by his wife, the soprano Judith Blegen; a sister, Cecilia Brauer, who is also a musician; a stepson, Thomas Singher; seven grandchildren; and two great-grandchildren. Another daughter from his first marriage, Davi Loren, died in May.

In 2000, in Met Orchestra concerts that were to be among Mr. Gniewek’s last, Mr. Levine gave him a rare honor by having him stand out in front at the program’s end to play Massenet’s Meditation from “Thais.” as an encore. When he did so at the New Jersey Performing Arts Center, Willa J. Conrad of The Star-Ledger of Newark wrote, “It was pure eloquence and grace, and as tribute to a particular musician’s legacy to a normally invisible orchestra, provided a particularly poignant close.”

When he did the same at Carnegie Hall two nights later, the ovation — from the orchestra as well as the audience — stretched past the five-minute mark, lasting longer than the solo itself.