Since her career began at the age of 18, Kass has featured in advertisements for designers including Calvin Klein, Chanel, Gucci, Donna Karan, Givenchy, Fendi, Valentino, Versace, Yves Saint Laurent, Chloé and Christian Dior. She also featured in campaigns for Revlon cosmetics and the Christian Dior perfume J'adore. Kass has been shot for the covers of numerous magazines including V magazine, Numero, Elle, GQ, Harper's Bazaar and several international editions of Vogue. She received the "Model of the Year" award at the 2000 VH1/Vogue Fashion Awards.