“I cannot change the way I am,” Julian Niccolini said as he nervously twisted a package of sweetener into a little ball. “I'm a people person. I love people. I'm never gonna change that, even when somebody tells me I'm a terrible human being.”

We were seated in the Pool Room of Julian's legendary Midtown Manhattan restaurant, The Four Seasons, at table 89, a perch from which, at lunchtime, one could take in the entire lustrous panorama of power diners reposed around a shimmering pool of water. A few feet away from us, at a lesser table, Niccolini had himself once sat as a customer.

It was 1977 and he was 24 at the time, an Italian émigré working as a waiter in a pricey French restaurant. His co-workers were always belittling the Four Seasons—too big, too impersonal—but he saw potential in its grandeur, in its prime location at the corner of 52nd and Park Avenue, and in its emphasis on seasonal ingredients. That summer night, Julian decided he would like to work at The Four Seasons.

And so the owners hired him to oversee the Grill Room, the cavernous walnut-paneled space down the hall from the Pool Room. Before long, he had helped transform The Four Seasons into the most consequential lunch spot in America—the culinary destination for visiting celebrities, the deal-cutting venue for CEOs. Thirty-eight years later, Julian Niccolini still lorded over the Grill Room and its billionaire habitués like their preening viceroy.

Soon all of this will change forever. A year from now, the restaurant will be gone, forced from the Seagram Building—the only home it's known since its creation in 1959—so that the building's owner, Aby Rosen, can install a restaurant of his own. A year from now, Julian might be a convicted criminal, perhaps done in by his inability to change while the rest of the world changes around him. For this past May, the 62-year-old co-owner is alleged to have assaulted a woman at the bar of the Grill Room—fondling her before she managed to break free and later bring a felony charge against him. To many who have observed his antics over the decades, the episode seemed not only plausible but also metaphoric, further evidence that both The Four Seasons and its frontman belonged to an earlier, brazenly chauvinistic era.

Julian sees the future quite differently. He intends to be cleared of the criminal charge against him. He also intends to disprove the insinuation that his shelf life as a restaurateur has expired. Julian and his longtime business partner, Alex von Bidder, plan to show that The Four Seasons can flourish elsewhere, even when stripped of its historical grandiosity and thrown into the shark tank of edgier restaurants run by culinary artistes half Julian's age. “People today want to have fun at restaurants,” Julian told me. He could adapt, he figured. Fun was his thing. Fun had always been his thing. Maybe people misunderstood this about him—that even his missteps were made in good fun. But he could not change who he was.

Before everything changes, you would do well to spend a couple of hours and approximately half your life savings at The Four Seasons. The Grill Room, designed by the famed architects Philip Johnson and Ludwig Mies van der Rohe, feels like a hypermasculine cousin of the Library of Congress, all wood and bronze and soundtracked by the low hum of commerce and the gentle swishing of the chain curtains.