Nancy Mullan is a Professional member of the American Society of Interior Designers, a Certified Kitchen Designer, and a licensed home-improvement contractor. She attended Vassar, the Sorbonne, the University of Perugia, and the Parsons School of Design, and she started her own design business in 1983.

Nancy designs homes primarily in the New York metropolitan area, including Manhattan, Greenwich, and the Hamptons. She has worked elsewhere throughout the United States, and as far afield as Lyford Cay in the Bahamas. Nancy's work has been published in several books and numerous national publications, and she is a regular participant in prestigious showhouses, such as Kips Bay, Southampton and Greenwich. Nancy is active in the National Kitchen and Bath Association (NKBA), both as a founding member of her local chapter, and on the national level. She appears frequently on TV, and she is working on a book about kitchens.