Zac Posen was raised in the SoHo neighborhood of lower Manhattan, the son of artist Stephen Posen and corporate lawyer Susan Posen. Zac Posen interest in fashion design started early, and as a child he would steal yarmulkes from his grandparents' synagogue to make ball dresses for dolls. Zac Posen attended Saint Ann's School, a private school in Brooklyn, and in his sophomore year interned with fashion designer Nicole Miller.
At age 16 he enrolled in the pre-college program at Parsons The New School for Design. Zac Posen graduated from Saint Ann's in 1999.
For three years Zac 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 College of Art and Design at the University of the Arts London.
During his tenure in London, Zac Posen found that the environment was competitive, while at the same time students were given a wide berth for independent learning. In 2001, Zac 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.
The gown was acquired by the Victoria and Albert Museum and featured in their "Curvaceous" exhibition.
In 2000, Zac Posen received a big break after a dress he made for Naomi Campbell (who had heard about him from Lola Schnabel, the daughter of American artist Julian Schnabel) changed hands several times among several fashion insiders, including actress Paz de la Huerta. He is famously well-connected and has called Lola's sister, Stella Schnabel, his muse.
Through Interview magazine Editor-in-Chief Ingrid Sischy, Zac Posen met his future publicist and event producer Ed Filipowski, of KCD who offered to represent him for free.
Upon returning to New York in 2001, Zac Posen set up an atelier in his parent’s living room, while they gave him a USD$15 allowance
In October of the same year he was chosen to present a capsule collection as part of GenArt's Fresh Faces in Fashion New York 2001. Zac Posen received a grant for USD$20,000.
After his first runway show in 2001,Zac Posen was courted by fashion titans Yves Carcelle (President of LVMH Fashion Group), Sidney Toledano (Chief Executive Officer and Director of Christian Dior S.A.), and Domenico De Sole (President and Chief Executive Officer of Gucci Group NV.)
Following the success of this presentation, Zac Posen established his design studio in Tribeca.
Zac Posen continues to receive awards and accolades, most notably the Council of Fashion Designers of America's 2004 Swarovski's Perry Ellis Award for Womenswear.
Zac Posen’s strong, feminine aesthetic has become a favorite of style leaders including Natalie Portman, Rihanna, Kate Winslet, Claire Danes, Cameron Diaz, Jennifer Lopez, Mischa Barton, Beyoncé Knowles, and many more.
In 2004, rapper and clothing designer Sean Combs made an investment deal with Zac Posen.
Ashley Olsen interned with Zac Posen in 2005 while a student at The Gallatin School of Individualized Study, an undergraduate college within New York University.In April 2008, Zac Posen's capsule collection created in collaboration with Target, Zac Posen for Target, was released in 75 stores in Australia.
A preview of the collection was shown during March's L'Oreal Melbourne Fashion Festival as one of the fashion week's headline catwalks.
