Karan began her career as an assistant designer with Anne Klein in the late 1960s, where she was promoted to associate designer in 1971. As Klein's assistant, Karan was a participant in The Battle of Versailles Fashion Show on November 28, 1973. When Klein herself died in 1974, Takihyo Corporation of Japan became the new owner and Karan, together with her former classmate and friend Louis Dell'Ollio, became head designer of the house. In 1984, Karan left Anne Klein and, together with her then husband Stephan Weiss and Takihyo Corporation, started her own business "to design modern clothes for modern people". She showed her first women's clothing collection in 1985.