Born in Bareilly, India in 1958, Khan grew up among textiles — his father and grandfather designed intricate clothing for India's royal families. In 1978 he moved to the United States to apprentice for Halston, mastering draping and garment construction while working around icons like Liza Minnelli and Andy Warhol. He launched the label Riazee, named for his mother, in 1981.
In 2003 he founded his eponymous house, selling at Bergdorf Goodman, Neiman Marcus and Saks Fifth Avenue and showing at New York Fashion Week. His gowns have been worn by Beyoncé, Taylor Swift, Jennifer Lopez and Penélope Cruz; Michelle Obama has worn the brand more than ten times since her first state dinner in 2009. He was inducted into the CFDA in 2008 and launched bridal in 2013.