Posen was raised in lower Manhattan, the Jewish son of artist Stephen Posen and corporate lawyer Susan Posen. His interest in fashion design started early, and as a child he would steal yarmulkes from his grandparents' synagogue to bell dresses for dolls. He attended Saint Ann's, a private high school in Brooklyn, and in his sophomore year interned with Nicole Miller.[1] At age 16 he enrolled in the pre-college program at Parsons The New School for Design.[2] He graduated from Saint Ann's in 1996. For three years Posen was mentored by curator Richard Martin at the Costume Institute of the Metropolitan Museum of Art. At 18, he was accepted into the womenswear degree program at London's Central Saint Martins University. During his tenure in London, Posen found that the environment was competitive, while at the same time students were given a wide berth for independent learning.[1] In 2001, Posen constructed a gown entirely made from thin leather strips and dress-maker hooks and eyes that delivered a powerful commentary about the female figure.[3] The gown was acquired by the Victoria & Albert Museum and featured in their "Curvaceous" exhibit.
In 2000, Posen recieved a big break after a dress he made for Naomi Campbell (who had heard about him from Lola Schnabel) changed hands several times among names such as Paz de la Huerta.[3] He is famously well-connected and has called Schanbel's sister, Stella, his "muse".[4] Through Interview magazine editor Ingrid Sischy, Posen met his future publicist (and show producer) Ed Filipowski, who offered to represent him for free.[4]
Upon returning to New York in 2001, Posen set up an atelier in his parent's living room, while they gave him a USD$15 allowance.[4] A year later he was chosen to present a capsule collection as part of GenArt's "Fresh Face in Fashion". He recieved a grant for USD$20,000.[2] After his first runway show in 2001, he was courted by fashion moguls Yves Carcelle (the president of LVMH Fashion Group), Sidney Toledano (the president of Dior), and Domenico De Sole (the president of Gucci Group).[5] Following the success of this presentation, Posen established his design studio in Tribeca. Zac Posen continues to receive awards and accolades, most notably the CFDA's 2004 Swarovski/Perry Ellis Award for ready-to-wear. Posen's strong, feminine aesthetic has become a favorite of style leaders including Kate Winslet, Claire Danes, Cameron Diaz, Jennifer Lopez, Helen Mirren, Mischa Barton, Beyoncé Knowles, and many more.
In 2004, rapper/fashion designer Sean Combs made an investment deal with Posen.[6] Ashley Olsen interned with Posen in 2005 towards her degree at New York University.[7]


