Who

The precocious and exceedingly ambitious Posen has been a fashion star since the tender age of 21.

Backstory

The son of a painter (dad) and a mergers and acquisitions attorney (mom), Posen grew up in a loft on Spring Street in SoHo where he was exposed to a heady mix of '80s art and finance types. His precociousness was evident early on: He showed up for his first day at Brooklyn's Saint Ann's dressed in a Charlie Chaplin-esque outfit and he spent his teen years as a social butterfly, hobnobbing with fellow scenesters like Lola and Stella Schnabel (Julian's daughters), Claire Danes, and Paz de la Huerta. His first exposure to the fashion biz came along at 16 when he landed an internship with the legendary Richard Martin of the Met's Costume Institute. After attending Parsons for a while, Posen dropped out and enrolled at London's Central Saint Martins College; he later abandoned the program to return to New York to start his label in 2001.

By the time Posen held his first runway show in 2002, he was already known as a young rising star with a keen eye for design and, perhaps more importantly, a gift for navigating Manhattan's social strata. Within two years, his clothes had made it to the racks of Barneys, Bergdorf Goodman, and Bloomingdale's, and he'd sold a 50 percent stake in his company to P. Diddy's Sean John clothing company for a reported $2 million. His arrival on the scene was confirmed that fall when he won the CFDA Swarovski-Perry Ellis award for emerging talent.

Of note

Posen has earned plenty of praise for his retro, well-tailored gowns and his shows regularly attract a Hollywood who's who—Natalie Portman, Anne Hathaway, Beyoncé, Angelina Jolie, and Naomi Campbell have all made appearances in recent years. But while there's little question that Posen's enormously talented, a good deal of his star status is thanks to his relentless networking skills, which hasn't always endeared him to critics. "A little bit adorable and a little bit awful," the Times's Cathy Horyn once mused, concluding that, "Success in fashion is one part talent, one part luck and one part a tireless ability to hold a gaudy marquee over your head. Posen has all these qualities in excess."

Since making a name for himself a few years ago—and following the Diddy investment—the fashion darling has followed a well-worn path of brand exploitation: In 2004, he introduced a "couture" cell phone for Nokia; a year later he created a limited edition denim line with 7 For All Mankind and introduced leather driving gloves on behalf of Jaguar. In 2006, he unveiled a collection of pricey handbags and a camera bag for Nikon. More recently, Posen announced plans to launch a fragrance line with Selective Beauty and partnered with Samsung on a series of Posen-designed cell phone "wallpapers." Now at work on a menswear line and a lower-priced diffusion collection, Posen's aggressive brand-building remains a family endeavor: Posen's lawyer mother, Susan, is the CEO of his company, Outspoke LLC, and his sister Alexandra serves as creative director.

Personal

Posen lives with his boyfriend, Brian Callahan, an interior designer who works for the architect Costas Kondylis. They occupy two floors of a West Village circa-1860 brownstone; the apartment is decorated with paintings by Zac's father, Stephen Posen, and more than a dozen pairs of antlers.

True story

Posen has long had a rep as a drama queen. In February 2007, when socialite and headband fan Arden Wohl arrived at his Fashion Week party having missed his show and, worse, wearing another designer's dress, Posen wasn't too pleased. "How dare you, you traitor!" he shouted, before having her thrown out.

No joke

Ashley Olsen was an intern at Posen's company.