"This is pretty close to my dream auction," says Niven, 61, who spent much of his youth at the Riviera estate of his father, the late actor David Niven, where prince Rainier and princess Grace were frequent visitors. "She took me under her wing when we lived in France, and I admired her greatly," he says.

He won’t mind if he overhears anyone at the auction whispering, "That’s David Niven’s son," but there was a time, particularly in the years following his father’s death in 1983, when he began to think enough was enough. After all, he had already purchased and sold a business, Aunt Millie’s Spaghetti Sauce, for a reported $17 million. "I was a pretty successful guy. I had a gigantic house in Southampton and all these dreaded possessions, and it started to get to me a little bit," he recalls. "But then, about five years ago, it stopped getting to me."

One of the reasons it has ceased to annoy him, he concedes, is that the current generation of young adults have no idea who David Niven was. "One of the young girls who came to work [at Sotheby’s] asked me, ‘Was your dad an important actor or a not-so-important actor?’" he says.

"It’s the scariest auction anyone can do. You’re on stage with Robin Williams, Jerry Seinfeld, Billy Crystal or Jon Stewart."

Niven stands a bulky 6 feet, 4 inches—other than the hooded eyes, he displays little physical resemblance to his father. At the podium, though, he is a showman in full command. But he didn’t start out that way when he began his career as an auctioneer 11 years ago.

He says the urge to try a new profession hit after Global Natural Resources, an oil and gas production company he had chaired, was sold in 1995 and he found himself without a job. "I always try to reinvent myself every 10 years," he says. "I got a call about doing business development for Sotheby’s, dealing with bankers and all the people I’d worked with over the years." A longtime trustee of the Museum of Modern Art in New York, Niven says he has always had a "dramatic" interest in art that started with his father’s collection of Ernst, Kandinsky and Chagall. Still, it is one thing to be an executive at Sotheby’s and quite another to be an auctioneer there, and Niven had to endure a strong dose of humiliation along the way.

Dede Brooks, CEO of Sotheby’s at the time, was less than receptive when Niven told her he would like to become an auctioneer. "I said, ‘I’ve had some success at charity auctions.’ She said, ‘That’s ridiculous. You’re too old and you shouldn’t be thinking about this.’ But I wanted to try anyway, so I started in arcade sales." Niven recalls the reaction of an old friend who attended one of his early attempts at auctioneering. "She said, ‘I suffered, like you suffered, through 20 lots, until they took you off. You were just horrible.’ I didn’t get much better for quite a while."

Niven reached a turning point on a night in 1997 when, faced with a heckler, he managed to win the crowd. It was an auction of what he calls 20 "really bad" contemporary works of art to benefit the Gay Men’s Health Crisis in Philadelphia. "In the middle of the sale, this guy gets up—he must have been 300 pounds—and says to me, ‘You’re the cutest little auctioneer I’ve ever seen, and I want to give you a kiss,’" Niven remembers. "There’s dead silence in the room. It’s a defining moment: whether you’re going to control it or lose it. I said, ‘If you don’t sit down, the next rather unattractive work that comes out, I’m going to sell to you.’ Everyone cheered, and after that I had confidence."