For an exclusive social club that prides itself on discretion and the privacy of its guests, Zero Bond in Downtown Manhattan has had no shortage of tabloid mentions.

Elon Musk hosted a party there after the Met Gala last September that was attended by Leonardo DiCaprio, Lil Nas X and Chris Rock. Gigi Hadid hosted her 27th birthday dinner there last month. Kim Kardashian and Pete Davidson went there on their second date. “Zero Bond feels like you’re in someone’s living room,” Ms. Kardashian said in an email.

And after Eric Adams was elected mayor of New York City last November, he headed to the club’s fifth floor, where he celebrated past midnight with the rapper Bobby Shmurda, the actor Forest Whitaker, and a room full of C.E.O.s including the former Google chief Eric Schmidt.

Mr. Adams has been sighted there so often that Curbed declared: “Zero Bond Is Eric Adams’s Headquarters Now.”

So it may come as a surprise to learn that the man behind Zero Bond describes himself as a “low key,” soft-spoken guy who was recruited by Columbia University to play tennis and fell into nightlife by accident.

“I have this unassuming magnetic personality,” Scott Sartiano said on a recent Tuesday night, sipping an old fashioned over a plate of seared scallops. He was seated in the club’s Baccarat Room, a private lounge reserved for founding members who enter using their fingerprint. “I’m the type of person who is so quiet, he’s monotone.”

Wearing a custom navy-blue blazer, black V-neck sweater and a titanium Audemars Piguet Royal Oak Offshore watch, Mr. Sartiano has a sensitive-jock look with hints of John Krasinski or Mark Ruffalo, depending on the angle. He had so many celebrity girlfriends that The New York Post’s Page Six once called him “the former man snack of Lindsay Lohan, Ashlee Simpson and Ashley Olsen, and the current squeeze of Jamie-Lynn Sigler.”

His philosophy in nightlife? “You can’t buy cool,” he said.

Yet, for much of the past two decades, that’s what he did. With his former business partner, Richie Akiva, he ran a mini-empire of downtown hot spots including Spa, 1Oak and Butter that distilled the essence of free-spending nightlife during the Bloomberg-era: Amex Black Card-toting hedge funders sipping $20 Grey Goose martinis, with model types in Louboutin heels.

But those days are over. Now 47 and married to Allie Rizzo, a Wilhelmina model, with a 4-year-old son, Henry, he not only runs one of the city’s hardest-to-join social clubs (some, he said, have attempted five-figure bribes), he was recently appointed by the mayor to one of the city’s most influential and coveted social positions: the board of the Metropolitan Museum of Art.

As for his old life? He no longer wants to stay up until 4 a.m. six nights a week, coddling V.I.Ps.“Nightclubs can suck the life out of you,” he said. As an old mentor once told him, “a club is a baby forever and you’re always going to be changing its diapers.”

Cashing Out of Clubs

“I was blown away,” Mr. Sartiano said, recalling the moment in 2017 that he first toured the 19th-century Victorian Gothic building at 0 Bond, its actual address, that long ago housed Brooks Brothers. “I thought it was the coolest address on the coolest street.”

He was considering a hotel, but the property was too small, so he pivoted to a “urban lodge and social workplace” for people like himself. “There was a void of places to go for people who are sophisticated and successful and still want to be social at night,” he said. “The business model with most clubs is basically, ‘How many people can you pile on top of each other?’ I wanted to do the opposite.”

Judging by the half dozen or more private social clubs opening in New York City these days (see Casa Cipriani, Casa Cruz and the Ned), he was clearly onto something.

Mr. Sartiano is coy about the club’s membership, except to say there is a waiting list of 8,000. Annual dues range from $2,500 to $4,000 (plus an initiation fee of $750 to $5,000), but money alone will not guarantee entrance to the club’s two floors of plush lounges, private dining rooms, omakase restaurant, screening room and library.

Admission, he said, is all about the mix and is decided by a membership committee.

“It’s a New York version of a London club,” he said. “New York is about mixing uptown and downtown, white and Black, artists and athletes.”

Among them is Tom Brady, a longtime friend. “Scotty has an unbelievable way of creating these environments for people to escape the challenging aspects of their work life and their personal life,” Mr. Brady said.

Becoming a social arbiter was the last thing he dreamed of, growing up in Columbia, S.C. Mr. Sartiano’s father, a doctor and a Brooklyn native, once told him that he was not cut out for the city. “He told me, “You’d never make it back in my neighborhood,’’ he said.

He arrived at Columbia University in 1992 to study political science. The first nightclub he visited, the Tunnel in Chelsea, was a shock. “Drugs everywhere, people making out,” he said. “This performance artist in a side room was sticking a yam up her vagina.”

After graduation, Mr. Sartiano hoped to make it as a novelist or journalist when a friend suggested he try his hand as a nightclub promoter to make ends meet. Before long, he was handing out drink tickets at Life, a 1990s club in Greenwich Village, where he met Mr. Akiva, a fellow promoter.

It was the late ’90s and the city’s nightlife was changing. Under Mayor Rudolph Giuliani’s quality-of-life campaign, club-kid palaces like the Limelight and Palladium were on the way out, replaced by upscale lounges for a new generation of young professionals living out their “Sex and the City” fantasies.

In 2000, Mr. Sartiano and Mr. Akiva opened Spa, a raucous dance club near Union Square where Justin Timberlake and Sean Combs would sometimes party. Two years later, they opened Butter on Lafayette Street, a rare fine dining establishment with a D.J. booth.

That is where Mr. Sartiano met Mr. Brady. “The thing that amazes me the most is, I have yet to crack Scotty’s loyalty to the Pittsburgh Steelers,” Mr. Brady said. “All these years I’ve been with the Patriots and now the Bucs, and he still does not give a damn.”

Next up was 1Oak, a 250-seat nightclub in far Chelsea with gold leaf walls and a revolving door of celebrities. It scored the nightlife equivalent of a benediction in 2013, when Jay-Z name-checked the club in “Beach is Better.” (“Started at the Darby, ended up at 1Oak, left the house with 100 grand, ended up near broke.”)

But by then, Mr. Sartiano was tiring of night life. In 2014, after getting married, he decided to sell his share of the company, the Butter Group, to Mr. Akiva.

“It sent shock waves through nightlife when Sartiano and Akiva split as partners,” said Michael Musto, the nightlife columnist for The Village Voice, which is back as a monthly publication and website. “They seemed to have a gift for making all kinds of people, especially high-profile celebrities, feel comfortable.”

It was an ugly split. Mr. Sartiano sued Mr. Akiva for $15 million, alleging that his former partner had underreported income and underpaid him in the deal. A lawyer for Mr. Akiva, Julian D. Perlman, said that the suit has no merit and that Mr. Sartiano has already settled his claims in previous agreements.

The suit is Mr. Sartiano’s last tie to his old club days. “You have an expiration date in the nightlife business,” he said, “and I expired it before it expired me.”

A Social Pivot

After polishing off his scallops, Mr. Sartiano talked about his next ventures, including a rooftop lounge and cafe at the Park Lane Hotel on Central Park South, and helping to reboot the celebrity-filled Mercer Hotel in SoHo, where he is a minority partner and creative director. (The hotelier André Balazs recently sold his stake .)

“We’re only two blocks away from Zero Bond, and the thought of merging his culture at Zero Bond into ours — his Rolodex and his curated community — would be really good for what we are,” said Richard Born, who owns the Mercer with Ira Drukier.

His appointment to the Met board is a social achievement of a different order and, in some ways, a curious one.

Mayors typically appoint a single person to the board to serve as a liaison to City Hall, and previous appointments have typically gone to establishment figures like Joseph Flom, the corporate law partner; Gail Hilson, a socially prominent fund-raiser; and Ken Sunshine, a public relations power broker with political ties.

But Mr. Adams has shown a willingness to buck convention when it comes to filling positions. As a nightlife entrepreneur in his 40s, Mr. Sartiano hardly fits the traditional Met board archetype, whose current members include Anna Wintour and Daniel Brodsky, a real estate developer and art collector.

Mr. Sartiano also has limited experience with government and art — although he does sit on Community Board 2 in Manhattan, and helps curate the rotating art collection hanging at Zero Bond, which includes works by Andy Warhol and Keith Haring on loan from members and friends.

Mr. Sunshine, for one, thinks his outsider status might be a blessing. “I would expect that a successful guy who owns clubs and restaurants would be welcome on the board, especially if he can bring others from his world to help raise money and attract younger people to the Met’s mission,” he said.

Mr. Sartiano’s role is not necessarily to raise money, but to have a direct line to the mayor, which he seems have to cultivated over many nights at his members-only club.

In a statement, Mr. Adams, who is not a member of Zero Bond, but reportedly comes as a guest of Ronn Torossian, an unofficial advisor, said: “I was not only impressed by his expertly curated art program at Zero Bond, but by his purpose-driven mission in utilizing the space and its members as a platform for young emerging local artists from New York City.”

Mr. Sartiano calls the appointment an honor, as well as a refreshing sign of this mayor’s leadership. “Nightlife is not a dirty word to him,” he said.