One recent frigid evening, a procession of 30-somethings wearing peacoats and high heels beneath puffy layers pushed past a curtain and walked into the elegant red saloon of the Nines, a new piano bar in the NoHo neighborhood of Manhattan that aims to fashion itself as a downtown Bemelmans. A pianist played jazzy covers of David Bowie and Chaka Khan tunes for guests nestled in fancy banquettes. Everyone seemed to be sipping martinis served with sidecars.

The buoyant crowd, appearing eager for a pandemic-era night out on the town, may have remembered Acme, the groundbreaking restaurant that closed quietly in 2020, which used to occupy this space on Great Jones Street. Or maybe they had once spilled drinks all over their coats in its basement night spot, Acme Downstairs, which is still going strong after a decade.

But nostalgia wasn’t in the air. Everyone was too engrossed in uni toast bites and potatoes heaped with Russian caviar (called the Kaspian Potato and priced at $95, it pays homage to Caviar Kaspia’s signature dish in Paris) to give very much thought to the past.

As they enjoyed the refined fantasy provided at the Nines, a man wearing a black velvet tuxedo jacket named Jon Neidich kept a close watch over things. Mr. Neidich is the chief executive of the Golden Age Hospitality group and the maven behind the establishment. Omicron wave or not, he projected the confidence of someone who has opened New York hot spots before.

“I like the uncertainty of opening night,” he said. “It’s an act of faith I’ve come to embrace.”

Mr. Neidich opened Acme in 2012, kicking off a craze for New Nordic cuisine in the city. But it was Acme Downstairs, the almost impossible-to-get-into subterranean lounge that he opened beneath it, that went on to define an era of preppy downtown millennial nightlife. Now, a father at 40, his dominion extends far past Great Jones Street.

Mr. Neidich has gone on to build a robust collection of trendy haunts across the city. In the West Village, there’s the Happiest Hour, a beach-resort-themed cocktail bar (its subterranean cocktail lounge, Slowly Shirley, closed during the pandemic). On the Lower East Side, there’s Tijuana Picnic, a chic and funky Mexican restaurant, and there’s also Ray’s, a retro dive bar that he opened with scene-makers like Justin Theroux, Taavo Somer and Carlos Quirarte.

Mr. Neidich’s stature as a player in the scene was elevated two years ago when he opened the French brasserie Le Crocodile at the Wythe Hotel in Williamsburg, which swiftly received a three-star review in The New York Times. On the Wythe’s sixth floor, he also runs Bar Blondeau, a natural wine bar with views of the twinkling Manhattan skyline.

But Mr. Neidich says his sleek new NoHo piano bar may be his most significant endeavor yet, at least for him personally, because it was at this very site that he hatched the beginnings of his hospitality kingdom a decade ago.

The son of a real estate financier, Mr. Neidich grew up on Manhattan’s Upper East Side and graduated from Hotchkiss and then Brown. He was a bacchanalian young man then, and he opened Acme in an especially uninhibited moment of New York nightlife that mostly now only exists in blurry Blackberry photos that survive to tell the tale. He managed Le Bain and Boom Boom Room before striking on his own, and when he did, he found himself with a sensation on his hands at the age of 30.

Teaming up with Indochine’s Jean-Marc Houmard and Huy Chi Le, he hired the chef Mads Refslund, a founder of Noma in Copenhagen, to run Acme’s kitchen, and the restaurant began catering to a burgeoning class of foodies who suddenly craved clams and scallops doused in foam served to them by waiters wearing skinny ties and tight jeans. Contemporaries like Aska and Atera soon joined the scene.

But this was also the era of Grumpy Cat and Robin Thicke’s “Blurred Lines,” and Roberta’s in Brooklyn wasn’t selling frozen pizza yet, and everything felt a little more carefree, so Mr. Neidich opened Acme Downstairs beneath the restaurant. Crowds began forming outside Acme at night, and if people got past the door, they descended into a dark grotto where a disco ball presided and tiny cramped bathrooms invited irresponsibility.

As time passed, Acme Downstairs became a nightlife mascot of sorts for a generation of New Yorkers.

There’s now a popular podcast, “We Met at Acme,” that examines the travails of millennial dating in the city, and when the company that manufactures M&Ms recently announced it was revamping its green M&M, replacing her go-go boots with sneakers, Rolling Stone published a salvo that defended her boots as a feminist fashion statement and proclaimed that she deserves to get “blackout” and be indiscreet “in the bathroom at Acme on a Wednesday.”

“Yeah,” said Mr. Neidich, sighing softly, when asked about the Rolling Stone article. “A friend sent that to me.”

As Mr. Neidich steps further into the limelight of the city’s elite hospitality scene, he can express bemusement about the legacy of what he birthed at Acme Downstairs, but he says he’s proud to have witnessed a fabled epoch in millennial New York nightlife.

“That whole era, from Bungalow 8 to Beatrice to the Standard, it felt like a moment, and Acme existed right on the cusp,” he said. “The advent of the camera phone as we now know it took away from the anonymity of being out at night. People still had a feeling of not being known and felt they could be freer.”

“We were among the last in a cultural change of how people went out in New York,” he added. “And downstairs we felt there was that safety and escape.”

Although Mr. Neidich is hardly pining with nostalgia for downtown Manhattan circa 2012.

He went off the grid backpacking in India at one point to purify himself from the intensity of his nocturnal lifestyle. Two years ago he embraced sobriety and he’s currently implementing a free counseling program for employees at his hospitality group who may be struggling with substance abuse. Nonalcoholic cocktails are becoming mainstays of his menus.

“Acme was the epicenter of New York, and after a decade it’s still going,” said the “Succession” actor Jeremy Strong, a close friend of Mr. Neidich, in a phone interview. “There’s been a metamorphosis in Jon’s life and work that I’ve witnessed, and there’s been a real journey from what Acme Downstairs was to what the Nines is.”

“McNally, Jeff Klein, André Balazs,” he added, “I see Jon in that trajectory ultimately and I think he aspires to that.”

In 2014, Mr. Neidich married Alessandra Brawn, a publicist and socialite, and their wedding in Italy featured contortionists and fire twirlers and was written up in Vogue. (They separated but remain friends.) He now lives in a loft on Lafayette Street and raises his 4-year-old son, Nash, with Ms. Brawn. He’s working on developing a wine bar in Chinatown and a French cafe cum raw bar in Williamsburg. And above all he aspires to open a hotel.

“I see an opportunity to create the next great downtown New York hotel,” he said. “All the great hoteliers, like Jeff Klein or Sean MacPherson, they create products I can see their soul in, and I see a chance for someone to be the next generation of that.”

On opening night at the Nines, Mr. Neidich’s parents, the financier Daniel Neidich and the jeweler and philanthropist Brooke Garber Neidich, slipped into a red booth for dinner, and as Ms. Neidich tucked into a caviar stuffed potato she considered her son’s journey from when he used to help her host gatherings in East Hampton.

“Hosting is in his blood,” she said. “It all goes back to when he was a boy serving hors d’oeuvres at our parties in Wainscott.”

“Acme is where he came from,” she continued. “We still have friends who ask us to help get their kids in. I’ll call him but he’ll ask me, ‘Is it just guys? Because I can’t let them in if it’s just guys.’ He’s strict even with me.”

While a pianist played bluesy tunes, and the elegant fantasy of the Nines carried on through the evening, Mr. Neidich attended to his guests. And as the night waned, young crowds began gathering outside in the cold, hoping to get into Acme Downstairs.

If they did, Acme’s glistening disco ball awaited them, defiantly continuing to spin.