Paul Morigi
Her handbags and ballet flats have been some of the hottest items at Bloomingdale's, Nordstrom, and Saks, for years, where she's competing with older, more established brands such as Coach, Michael Kors, and Kate Spade.
Her company, which was founded out of her kitchen in 2004, is now valued at more than $3 billion.
She was recently asked about her biggest challenge in creating such a succesful brand, and she had a surprising answer.
"Gaining confidence to really believe in myself was a big one," she told television host Charlie Rose in an interview published by Businessweek.
"I had an article written on our company, the first article. And a great friend called and said, 'It was a great article, but you shied away from the word ambition.'
"When I thought about it, she was absolutely right. And I was kind of mad at myself, because I was raised with three brothers not knowing there was any difference in what we could do. Our parents made us believe we could do anything. When I really looked at that article, and looked at myself, I realized I was a little timid when facing that word - and it was something I wanted to change."