Most top execs of young fashion labels would kill for the opportunity to be carried by Bergdorf Goodman, the renowned luxury department store, but not Wen Zhou of 3.1 Phillip Lim.

When Bergdorf buyers requested Lim’s line in the spring of 2006, the label’s sales were skyrocketing. But C.E.O. Zhou was concerned that taking on another major customer at that time would overwhelm the company’s overseas manufacturers or worse, flood the market with too many clothes and have her fledgling label’s brand diminished by its appearance in the discount bin.

“We wanted to cement our feet in the market even more, really take care of the retail doors that we were already in,” Zhou says.

Zhou held Bergdorf executives at bay for more than a year before finally agreeing to take on a relatively small initial order that could increase over time. Bergdorf will begin carrying 3.1 Phillip Lim starting in January.

It’s just this judicious approach that has put the company on a fast track to profitability and $30 million in revenue for 2007. The press has tended to focus on the line’s sophisticated and finely crafted yet modestly priced clothes, but the secret force behind the label’s business success is a petite Chinese American woman who, at 34, is already a seasoned veteran of the fashion business.

“It’s not enough just to have very successful designs and a consumer following,” says Kate Sayre, a managing director of Boston Consulting Group, in New York, whose clientele includes fashion companies and luxury retailers. “There are plenty of designers that have products to sell but are not profitable.”

So Lim has Zhou. Introduced by a mutual business acquaintance, the pair became fast friends, starting the label three years ago, when they were both 31 years old (hence the name 3.1). Lim had just been forced out as the chief designer of a small Los Angeles label after clashing with his business partners over the line’s creative direction, and he was searching for his next design project. Zhou had experience and capital from running two other apparel-related businesses that she started herself—the import-export company Aegis and the sourcing agency Gwendolyn, which connects U.S. designers with factories in China. Upon finding out that Lim was unemployed, she immediately asked him if he wanted to partner with her on a new label.

“I just loved his aesthetics,” Zhou says. His clothes “make women feel a lot more confident.”

Lim quickly said yes. “At that point, I had nothing to lose,” he says. Zhou put up $750,000 in startup capital that she obtained from her two businesses and a loan against her apartment, and the two decided that they would target a market niche that they felt was underserved—designer-quality fashions, but at a fraction of the price. A pair of 3.1 trousers, for example, starts at about $300, while 3.1’s dresses retail for $500 to $700.

“For the quality, it’s really inexpensive,” says Terence Bogan, a vice president at Barneys Co-Op, where, Bogan adds, 3.1 is among the bestselling women’s clothing brands. “A coat would retail for $795, but when you look at the construction, the coat could easily be a designer coat at double the price.”