Bill Marriott, left, at the ribbon cutting Tuesday for his newest hotel in D.C., toasts the occasion with root beer with Mayor Vincent Gray. (Bill O'Leary/The Washington Post)

He’s 82 now, but Bill Marriott can’t bring himself to completely walk away from the company that bears his name. On Tuesday, the octogenarian presided over the grand opening of the gleaming 1,175-room Marriott Marquis, the new convention-center hotel in Northwest Washington that his family considers one of its proudest legacies.

“I really do wish my parents could be here to see this wonderful and monumental hotel,” Marriott told about 200 guests, who toasted the hotel with root beer to honor the nine-stool District root-beer stand that begat a hotel empire.

Though Marriott no longer runs the company he transformed into a global lodging chain, he remains its executive chairman, still working 50 hours a week and visiting more than 200 hotels a year. In the process, he has become one of the country’s most prominent everlasting executives, a small but high-profile group of golden-aged titans whose identities and personal fortunes are so wrapped up in their firms that the concept of retirement is incomprehensible.

Many of them bear famous names: News Corp. chief executive Rupert Murdoch (age 83), Viacom Chairman Sumner Redstone (91), Berkshire Hathaway investment legend Warren Buffett (83) and Marriott, who ran his company for 39 years. But there are less prominent ones, too. Melvin Gordon, chief executive of Tootsie Roll Industries, is 94. O. Bruton Smith, the chief of Sonic Automotive, a Fortune 500 group of auto dealerships, is 87.

Owning large stakes gives these executives the ability to essentially hang around as long as they please. But academics who study and interview older executives say there is a complicated psychology at play and that advances in health care — Marriott has survived several heart attacks — mean the country could see more everlasting executives in the future.

Marriott at the newly opened Marriott Marquis Hotel in Washington on Tuesday. (Nikki Kahn/The Washington Post)

What motivates them? For starters, death.

“One way of pushing death away is hard work,” said Manfred F.R. Kets de Vries, who studies management psychology and is the author of a paper titled “Death and the Executive: Encounters with the ‘Stealth’ Motivator.” “Work is a way of not thinking about it, as opposed to sitting on the golf course and having some drinks. It’s about finding and having meaning.”

Though there are studies showing that the older executives get, the more risk-averse they become, potentially robbing shareholders of big acquisitions that could improve company’s bottom line, that drawback, some experts say, is ignored by corporate boards too worried about pushing out popular figures whose identities would vanish without their jobs.

A report by the Conference Board, a business research group, showed that mandatory retirement policies are now seldom used. And the idea of everlasting work is filtering down to the lower executive ranks, with surveys by Gallup and others showing that large numbers of baby boomers intend to put off retirement because they find work rewarding or because their retirement accounts took a beating in the recession.

Some 10 percent of organizations now offer some form of phased retirement, according to the Society for Human Resource Management.

“If you have reasonably good health and a real interest in what you’re doing, there is no reason why you can’t continue contributing for as long as you can,” said Fred Malek, a close friend of Marriott and former president at the company. (He’s still working at age 77.) “People like Bill are lucky to have that.”

Marriott’s everlasting career is somewhat rare when compared to Murdoch, Redstone and Buffett, all of whom still wield considerable day-to-day control over their companies. Marriott’s stepping away was the subject of intense speculation over the years, especially after his son John left the company in 2005, leaving no other family member ready in age or experience to fill the top job.

Marriott turned to Arne Sorenson, a young, well-liked executive he had personally groomed. Sorenson said he regularly consults with Marriott — whose office is just down the hall at the company’s Bethesda, Md., headquarters — not because he has to but because he wants to. Marriott, he added, remains deeply interested in hotel operations and isn’t shy about bringing up ideas or problems. He attends monthly senior staff meetings.

In Marriott, Sorenson has a counselor with such love and recall for details that in an interview he offered the secret to a famous Hot Shoppes dessert: “The key to our hot-fudge ice-cream cake was to leave a spot in the middle of the cake on the top and not cover it with anything, so you could put your whipped cream and cherry on a dry spot. If you put it on top of the chocolate, it would slide off, and you wouldn’t have good ice-cream cake.”

By hanging around, “Marriott is hedging a bit and making sure his successor lands on his feet,” said Donald C. Hambrick, a management professor at Penn State University who has studied lengthy executive tenures. “He is showing that he’s pulling for Sorenson and doesn’t want to leave him high and dry.”

Asked what he thinks Marriott gets out of his role, Sorenson said: “It keeps him young and active and engaged. He’s a big competitor. He wants to win.”

His family thinks they win, too.

“My dad will never stop working,” said daughter Deborah Marriott Harrison, “and we’re happy about that because he would probably curl up in the fetal position and die, because this company has been so much a part of his life.”

But he’s no longer putting in 80 hours a week. They get more of him at home.

“He’s less preoccupied and more in the moment,” Harrison said. Earlier this year, Harrison saw him play a game with one of his 15 grandchildren — a fishing expedition with magnets. He and his granddaughter played for 45 minutes.

Who won?

“Are you kidding?” Marriott said, laughing. “She won.”