Smith trained at the Fashion Institute of Technology and interned in the Paris ateliers of Hermès, Louis Vuitton and Christian Dior Haute Couture before returning to New York. Built on a $50,000 investment from Oshrin, MILLY met its first-year sales goal in three months and grossed $11 million annually by 2005, opening its first Madison Avenue boutique in 2011.
The label's collections merge American sportswear with Parisian atelier techniques and custom prints across ready-to-wear, accessories, swimwear and childrenswear. Worn by Beyoncé, Gwyneth Paltrow and Kate Middleton, MILLY was chosen by Michelle Obama for her National Portrait Gallery dress. Smith and Oshrin sold the company to S. Rothschild in 2019.