He Wanted to Be Pope. He Settled for Conducting the Metropolitan Opera.

The Quebec-born music director Yannick Nézet-Séguin has soared to the peak of his profession thanks to his precocious talent and a belief in “smiles and optimism.”

Yannick Nézet-Séguin during a rehearsal of the Orchestre Métropolitain in Montreal.
Yannick Nézet-Séguin during a rehearsal of the Orchestre Métropolitain in Montreal.Credit...Renaud Philippe for The New York Times
Dan Bilefsky

MONTREAL — When the conductor ​​Yannick Nézet-Séguin was 10, he went to the basement of the family house, put on one of his parents’ vinyl records, held a yellow pencil aloft and began to conduct the first movement of Mozart’s Symphony No. 40, over and over again.

For the previous four years, the boy, obsessed by the rituals and pageantry of the Roman Catholic Church, had gone to the basement every day to conduct Mass by himself, earnestly telling his parents he wanted to become pope. So when he went upstairs to announce his new vocation, his mother and father, engaged in a game of after-dinner bridge, were ​amused.

“I was abnormally intense,” Mr. Nézet-Séguin, now 44, said with a laugh in between rehearsals at the Place des Arts concert hall in Montreal. “At that moment, my fascination with reli​g​ion was transferred to music and the liturgical aspect of the church became the ritual of the concert. My parents said, ‘Oh, whatever. In two weeks, you’ll want to become an astronaut.’ But I never changed my mind.”

Mr. Nézet-Séguin, who sometimes bleaches his short-cropped hair a vivid blond, has not disappointed his 10-year-old self. Last year, he became the third official music director in the history of the Metropolitan Opera in New York (“I expected his ‘Traviata’ to be good, but not this good,” wrote The Times’s chief classical music critic of the first opera that Mr. Nézet-Séguin conducted in his new post).

The triple role can be punishing for Mr. Nézet-Séguin, who shuttles frequently between the three cities and to recording sessions and about 120 concerts a year. But the indefatigable maestro, who communes with classical music scores even while in the bathtub, said that he also required solitude. He decompresses by swimming, listening to the French diva Dalida and drinking champagne.

“Yes, I am very busy and high energy, but I am not hyperactive,” he said, switching seamlessly between French and English. “The loneliness of studying a score is one of the things that attracted me to becoming a conductor.”

Mr. Nézet-Séguin retains a deep affection and loyalty for his hometown, Montreal, where he got his start. At 21, he conducted Bach’s “St. John Passion” in a former church. It was his first public concert with a choir and instruments. He was so overcome, he said, that he could feel himself floating up to the chapel’s ceiling. “I felt as if I was levitating,” he recalled.

More than two decades later, he appeared similarly elated when his Orchestre Métropolitain, long in the shadow of the Montreal Symphony Orchestra, premiered at Carnegie Hall on a recent evening. When the audience erupted in a standing ovation after a haunting performance of Anton Bruckner’s Fourth Symphony, his eyes moistened with emotion.

For years, there was speculation that, as his stature soared, he would abandon the Montreal orchestra, which he began conducting at age 25. But Mr. Nézet-Séguin said he was determined to remain connected to his Quebec roots and to an orchestra he calls “my family,” in which his partner, Pierre Tourville, plays viola.

Mr. Nézet-Séguin cites his native Quebec as a reason for his informal and egalitarian conducting style. “Our ancestors are mostly peasants and farmers, and there has long been a distrust of authority,” he said.

A mixture of decisiveness and gentle cajoling was on display in a recent rehearsal of the Orchestre Métropolitain for a performance of Berlioz’s “Harold in Italy.” Wearing sweatpants, a black T-shirt and running shoes, he used his whole body to express the music’s sweep, rising up and down on his toes on the podium with balletic athleticism.

“Too fast,” he told the brass section at one point. He sang out how he wanted the phrasing. He addressed all the players and not just the principal musicians. “Let’s return to that musical orgy part,” he said during a pause, eliciting laughter from the musicians, who addressed him as “Yannick.” Finally satisfied, he gave two thumbs up.

Mr. Nézet-Séguin says he believes that conducting has too often been dominated by black-tailed deities. “The aim of my conducting is to elicit emotions from my players,” he said. “Being demanding is not the same thing as making people afraid.”

Jean Paquin, a French horn player at the Orchestre Métropolitain who has known Mr. Nézet-Séguin for two decades, said that when the conductor arrived at age 25, some players had been skeptical. But Mr. Nézet-Séguin quickly convinced the doubters with his humility, his passion for the music and his “expressive, supernatural left hand,” Mr. Paquin said.

Mr. Nézet-Séguin said he had always admired Leonard Bernstein, “primarily because there was never a note that was not filled with intention or emotion.”

Then there was his “maestro,” the Italian conductor Carlo Maria Giulini, whose music Mr. Nézet-Séguin discovered as a boy before studying with him in the late 1990s. “He was very calm and never used harsh words,” Mr. Nézet-Séguin said.

He added that he was determined to bring such equanimity to the Metropolitan Opera after “troubled times.” In 2018, Mr. Nézet-Séguin became the Met’s music director after the previous holder of the role, James Levine, was fired over allegations of sexual abuse that he denied.

Mr. Nézet-Séguin’s aim for the Met, he said, was a new era of optimism through a “quiet revolution,” an allusion to a 1960s social movement in Quebec against the strictures of the Catholic Church. “I don’t believe in arriving at an institution and being a disrupter,” he said. “There is some resistance — I am not saying it’s always easy — but smiles and optimism are what is needed.”

Born in Montreal into a churchgoing family, Mr. Nézet-Séguin gave credit to his parents, both professors of education, for accepting their gay son and for giving him the confidence to be himself, on and off the podium.

His parents, in an interview in New York, said he was a born performer, putting on musical shows for his two elder sisters, dancing to Michael Jackson hits and constantly drawing.

At age 12, he began studying piano, composition and chamber music at the Conservatoire de Musique in Montreal, before founding his own orchestra and Baroque choir, La Chapelle de Montréal. “I never really properly studied conducting. I developed as a musician and eventually conducting became an extension of that,” he said.

His father, Serge Séguin, said that when his son was 15, he had persuaded him to pay 600 Canadian dollars, about $520 at the time, to go to Montreal’s towering Courthouse and add his mother’s maiden name, Nézet, to his surname. Séguin is a common name in Quebec, and the teenager thought that a double-barreled name would help him stand out as an artist.

“He had a vision of what was necessary to accomplish his ambitions,” Mr. Séguin said. “At that age, he was already thinking of his future on the global stage.”

In 2000, Mr. Nézet-Séguin became conductor of the Orchestre Métropolitain. He recalled that when Mr. Tourville, his partner, had tried out for the ensemble from behind a curtain, he had recognized his viola playing immediately. “It was the warmth,” he said.

The two met as students at the Conservatoire and Mr. Nézet-Séguin, who had a girlfriend at the time, said the relationship had gradually blossomed. Being an openly gay conductor, he added, was still woefully rare. “I want to be a role model for young people,” he said.

Mr. Nézet-Séguin’s big break as a conductor came in 2008 at the internationally celebrated Salzburg Festival, where he conducted Gounod’s “Romeo and Juliette Overture.” He was so nervous at one public dress rehearsal that he began by conducting the wrong piece, “The Flying Dutchman” by Wagner, he said.

But his performance turned out to be a triumph, propelling his international career and leading to appearances with the world’s greatest opera houses and orchestras.

Conducting, Mr. Nézet-Séguin said, sometimes required embracing the unexpected.

Once, at the end of a performance in Montreal of the Alban Berg opera “Wozzeck,” he recalled, a musician’s cellphone played a honky-tonk tune just as the opera was ending with a boy dancing with a hobby horse.

“It matched the scene onstage so well that people said, ‘Oh my God, this is genius!’” he said.

Too many of today’s conductors, he added, were too controlling. “The danger is to become too dry, too academic,” he said, “That the mind takes too much space compared to the heart.”