On April 17, roughly 800 well-heeled well-wishers filled three floors of the fabled Manhattan eatery “21.” A regatta of navy-blue jackets and charcoal suits sailed through the Harbour Room. In the Puncheon Room one floor below, hands wreathed in French cuffs and jeweled bracelets lifted bluepoint oysters and Veuve Clicquot to their lips. Graying captains of industry lounged in familiar leather chairs beneath Remington originals.

In the famed Bar Room, newspaper columnist Sidney Zion savored a Bombay martini and growled how, before the Bloomberg smoking laws, it was three deep at the bar every night. Somewhere – the Winchester Room? – FBI Assistant Director James Kallstrom enjoyed a night off, while Ed and Tricia Nixon Cox stared up at the ceiling plaque beneath which their presidential father used to dine. Off in a corner, former Miss America Phyllis George touched up her lipstick, and Bill O’Shaughnessy, the author and radio commentator, shook his white mane before rising to speak about the man in whose honor all of the above had gathered.

That was Bruce Snyder – aka “Mr. Bruce” – an elegant, poised Oklahoman who has played host at “21” since 1969. As such, he has for decades maintained the relaxed yet precise equilibrium that characterizes what is arguably the most storied saloon in New York City. He will retire in mid-May.

“He’s the keeper of the flame, protector of traditions and the heritage of ’21,'” said Mr. O’Shaughnessy to the gathered crowd. “He is an expert at classic, stylish, timeless hospitality. People come here to hear the one word they hear in their dreams.” Mr. O’Shaughnessy then adopted a comically plummy, soft “L”-ed accent to utter his two-syllable Snyder imitation: “Hello.” A wave of laughter interrupted him before he could ask, rhetorically, “Does everybody talk like that in Oklahoma, Bruce?”

Mr. Snyder – whose slicked-back brown hair, parted exactly in the middle, does not answer to the age 66 – was brought into the fold 36 years ago by the Kriendlers and the Bernses, the two related clans who established “21” in Prohibition days. “I was the first person outside of the family that was asked to stay around,” he explained. “They adopted me.” The owners eventually sold their interest in the mid-1980s, leaving Mr. Snyder as the most visible living link to the boite’s founding management. “I’m the last of the old-timers,” he modestly allowed.

Mr. Snyder was raised Covington, Okla.; his father ran a grain elevator and feed store there. Eschewing dad’s wheat fields, he graduated from Oklahoma State with a degree in hotel and restaurant management and immediately signed on with the Marriott Corporation. It was Marriott that sent him to “21” to study the possibility of transplanting the restaurant’s food and ambience to airplane cabins (an extraordinary concept in these pay-per-pretzel times). As it happens, Mr. Snyder is not the only Sooner to make good in swank New York society. Sherman Billingsley, who founded the famed Stork Club, grew up in Enid, Okla., just a few miles northwest of Mr. Snyder’s tiny hometown.

“I was here 18 months,” he said. “I was supposed to be here three months. They took a liking to me, and they asked me to stay during that time. When Mr. Marriott said come back, I knew I didn’t want to go back into a flight kitchen again. I wanted to deal with the public. So I immediately transferred to the hotel division of Marriott. A week before I was to report, I called Bob Kriendler to tell him of my plans, and he said, ‘You’d better come see us.'” Mr. Bruce was born.

Everyone who knows Bruce Snyder talks of how he puts you at ease. That he does. He also, however, puts you on guard. Confronted with his finely groomed countenance, you straighten your posture and hush your delivery. How else to react to a man in the following ensemble: dark blue, double-breasted, pin-striped suit; off-white vest; French-cuffed blue shirt with white spread collar; and black-and-white patterned tie? It’s not for nothing that one partygoer joked that Mr. Snyder wasn’t retiring, but had in fact bought the men’s clothing department at Bergdorf Goodman.

“The first time I came here, I had on a black-and-white checked jacket,” remembered Mr. Snyder. “And then I met all these gentlemen who had on their dark blue suits or dark gray suits. I immediately knew I had some problems with my wardrobe.” Bob Kriendler solved that dilemma in 10 minutes. That’s how long it took him to walk his protege across 52nd Street to L. Greif Brothers and select six suits for him.

Mr. Snyder has picked up more than a taste for fine attire in his 36 years of service. He’s also developed a finely tuned set of antennae. Fully attentive during our interview, his cool gray eyes would nonetheless occasionally narrow and sneak glances to the left and right. Almost imperceptibly, he monitored the goings-on in his domain. He needn’t have. At 5 p.m.- and seated as we were in the section patrons call Siberia and Mr. Zion terms the Bay of Bigs – the place was nearly deserted. But inattention is not Mr. Snyder’s style. A complacent mind would not be ready for the next familiar or famous face to cross “21”‘s iron gate.

And over the years, he has greeted them all, including the Duke and Duchess of Windsor, several dozen CEOs, a fair share of movie stars, Margaret Thatcher, Chelsea Clinton on her 18th birthday, and every president since Nixon. Well, almost every president. “George W. has not been here yet,” Mr. Snyder admitted, fingering the commemorative Bush White House cufflinks that, perhaps, he wears as a charm to lure the dilatory commander in chief. “His wife has been here. His children have been here. We’ve got to work on him.”

Should W. choose to catch Mr. Bruce’s act before he retires with his wife to Williamsburg, Va., he would have his choice of seats. That is, unless his father, a “21” regular, were on the premises and wanted the same table. In that case, smiled Mr. Snyder, “Seniority rules. Whoever’s been coming the longest.” And the losers in such competitions – they take it calmly? He hesitated and inclined his head slightly. “Usually. Or we have to talk very fast to get them to understand.”