The Owners of Eleven Madison Park Are Ending Their Partnership

New York’s most powerful restaurant marriage has come to an end.

The chef Daniel Humm and his business partner, Will Guidara, who in 2011 bought the elegant restaurant Eleven Madison Park from their mentor, the restaurateur Danny Meyer, and transformed it into one of the world’s most lauded dining destinations and the crown jewel of a restaurant group that stretches from London to Los Angeles, are splitting up their multimillion-dollar partnership.

With help from an investor, Mr. Humm is buying out Mr. Guidara’s share of the business. Mr. Guidara plans to use the money to open his own restaurant group. Neither would disclose the financial terms of the deal.

Although some top staff members of the group had known about the pending breakup for weeks, most of the staff of about 1,000 people found out today in an email.

“It’s been an incredible run and I think we both learned a lot from each other, but we also have evolved in different ways,” Mr. Humm said in a joint interview with Mr. Guidara. “We’re extremely proud. We just came to the conclusion in the end that what would be best for the company is if I continue to run it.”

Mr. Guidara said that he would make public details of his plans soon. Mr. Humm said operations would largely remain the same but he plans to make some staffing changes, including the promotion of Jeffrey Tascarella to chief operating officer.

The two have joked that they resembled a married couple who rode ups and downs and sometimes fought in front of the children. As the chef Wylie Dufresne told Esquire magazine in a 2017 profile of Mr. Humm, “It’s not like they’re stuck with each other but the rise of each of them has been linked to the other. That relationship has helped to define a lot of decisions he’s made. It’s not totally clear where one starts and the other ends.”

But by the beginning of this year, it was clear they were both ready for the relationship to change. They spent months examining a number of scenarios, including trying to find a way to stay together. But in the end, the path seemed clear.

“We spent a long time trying to divide the company and it just wasn’t working,” Mr. Guidara said. “It’s a big company with lots of moving parts.”

The men’s relationship started in 2006, when Mr. Meyer lured Mr. Humm from San Francisco to conjure up dishes that could match the majestic dining room at Eleven Madison Park, and promoted Mr. Guidara to manage the restaurant. The men were young and ambitious, determined to make their mark inside the marble walls of a revered piece of New York culinary real estate in the Flatiron district.

They became as tight as brothers — best friends, as they often referred to themselves in interviews. Their emphasis on hyper-personalized service and precise cooking propelled the restaurant to the top of nearly every critic’s list and brought a cascade of awards. In 2011, Mr. Meyer sold Eleven Madison Park to Mr. Guidara, Mr. Humm and their financial backers.

Mr. Guidara and Mr. Humm created a company called Make It Nice that spawned a family of six other bars and restaurants, including the NoMad in the NoMad hotel in Manhattan, as well as NoMad restaurants in Los Angeles and Las Vegas. They also own Made Nice, a casual restaurant near the hotel that serves charred avocado and kale salads and roasted chicken with fries intended to become a mini chain. (Mr. Humm said he will continue with his plan to open the restaurant Davies and Brook in the Claridge’s hotel in London this fall.) They have written four books together, too.

But after 13 years, the partnership grew rocky. They and others close to them say they have clashed as both they and the company have grown.

“We’re not going to lie to you and say things are hunky dory,” Mr. Guidara said in an interview in April. “We’ve been in a season of tension.”

Still, both men described the split as an amicable one, with Mr. Humm taking control of their empire and Mr. Guidara developing plans for a new one.

The clear prize in the deal is Eleven Madison Park. With its soaring ceilings, marble walls and dramatic windows, it is one of the country’s most expensive restaurants. A tasting menu costs $335 per person before drinks or tax, and dinner can stretch into a four- or five-hour affair.

Mr. Meyer opened the restaurant as a French-influenced bistro in 1998 in the lobby of the old Metropolitan Life Building. Eight years later, he brought in Mr. Guidara and Mr. Humm.

The men took on the challenge of turning Eleven Madison Park into something spectacular with a drive and enthusiasm that made even jaded New York chefs take notice. The menu was controlled and ambitious, and it reflected the precision and personality of Mr. Humm, who learned to cook in his native Switzerland and left a prime post as a four-star chef at Campton Place in San Francisco to work for Mr. Meyer. Mr. Guidara, who learned the trade at the hands of Mr. Meyer, was as focused in the dining room. His training manual for staff was 97 pages long.

The wunderkinds weren’t always on the mark. In the early years, they had a difficult time gaining traction, and sometimes only served 10 tables a night. Then, in 2012, a year after they bought the place, they blew up the elegant, restrained menu and turned dining there into a tribute to old New York, with card tricks, a tabletop clambake and a cheese course in a handmade picnic basket. Pete Wells, the restaurant critic for The Times, later called it “the most ridiculous meal I’ve ever had.”

The pair eventually pulled back on the shtick, created a new menu and doubled down on a brand of service so personal that waiters were encouraged to glean information from customers so last-minute surprises tailored to each diner’s interest would appear at the table before the meal was done. And, as had long been the custom, each would leave with a jar of Mr. Humm’s granola for breakfast the next day.

The new menu brought another four-star review from Mr. Wells in The Times and, in 2017, Eleven Madison Park climbed to the top of the annual World’s 50 Best Restaurants list.

That year, the restaurant closed for four months so the architect Brad Cloepfil could redesign it. It reopened in October with a modern, crisper look. The seating was more intimate, the entrance more dramatic and a large painting by Rita Ackermann, a friend of Mr. Humm’s, dominated the dining room.

Meanwhile, life has changed for the men, too. Their personal lives have matured. What had been a near-singular focus on their work gave way to new and changing relationships. Mr. Guidara married Christina Tosi, a founder of the Milk Bar chain, in 2016. Mr. Humm has three daughters with two different women. After some time as a single man, he is pursuing a new relationship, too.

“As the founder of that restaurant and the person who introduced the two of them, I’m both proud of what they achieved together and sad their partnership is concluding,” Mr. Meyer said. “On the other hand, I hope we will now get to see an amazing next solo chapter for each of them. It certainly happened for Lennon and McCartney.”