As a teenager, handsome Harald Grant launched a modeling career with the famous Ford Agency in New York. Within a few years he was a familiar face in Seventeen magazine and Gentleman’s Quarterly (GQ). He ended his modeling career at 27 and was running a horse farm on Long Island when he decided to supplement his income by selling real estate. It turned out to be the best decision of his life. Today, at 55, he’s one of the top-selling real estate brokers in the world with last year’s sales exceeding $244 million.

While it can’t hurt to have good looks, Grant says the key to his success at Sotheby’s International Realty is the same as any broker’s: credibility and knowing his market. Of course, it helps that his territory is the Hamptons, a mecca for the super-rich. Even before F. Scott Fitzgerald wrote The Great Gatsby, there was no greater status symbol in America than a home in the Hamptons. Current residents include Katie Couric, Sting, Betsey Johnson, Billy Joel, Donna Karan and Puff Daddy – and that’s the B-list.

Grant’s list of elite clients includes European royalty, Hollywood celebs, business tycoons and fund managers. "They expect you to know your industry like they know theirs," he says. "And their time is precious. They may land in a helicopter and have two hours, so you’d better know what you’re doing."

With this kind of client, price can be a non-factor. But Grant feels it’s important to caution the buyer who may be overspending on a property.

“People make emotional buys all the time,” he says. “If they can’t get their investment back in six months, they’re buying emotionally. I always let them know. Then they can decide.”

Apart from the mind-boggling commissions he earns, Grant says he enjoys meeting people who lead interesting lives. He gets invited to a lot of lavish parties, and some clients voluntarily pass along his name to their equally wealthy friends.

Grant won’t disclose clients’ names for publication, although off-the-record he mentions a world-renowned family associated with newspaper publishing. (Hint: “Citizen Kane.”) Seriously, his respect for confidentiality is another reason clients trust him.

It shouldn’t surprise anyone that this kind of phenomenal success has its price. How does Grant relax? "Hmmm, that’s a good question." After a pause, he says, "Running on the beach breaks up the day. I mean, I work all the time. You have to if you want to be successful. This business is very competitive because the money is so large. And because I’m always working, that has ruined some relationships."

One thing Grant has learned from selling super-sized mansions is the more costly the property, the less complicated the transaction and the smoother the closing. Last year he sold six oceanfront homes for more than $20 million each. (This year, he says, those same properties would fetch more than $30 million.)

“What I find interesting in my marketplace is how little knowledge the (clients) have,” he says. “They come to you for that. Being honest with them from the very first moment is critical. I always tell people, ‘Don’t rush.’ There’s always something to buy. That surprises them. ‘Why are you talking me out of buying?’ they ask.

“In a market like ours, the seller can afford to be firm on his price. And where there’s exceptional wealth, the selling price has a lot to do with ego: ‘If you want my house, you have to pay my price.’ But sometimes when the buyer refuses to pay it, the next year it’s 20 percent higher."”