Miller Gaffney has a wide-ranging background in the art world, having worked with leading auction houses, commercial galleries, artists, museums, and information-providers for art collectors. She began her career with L'Antiquaire & The Connoisseur on New York's East 73rd Street where her responsibilities included assisting in the purchase of artworks and antiques on behalf of collector clients from international auction houses. In 2004, she joined Art + Auction magazine. She was later called by its parent company, LTB Holding, to work as a Business Development Officer. While in these positions, she also worked as a private consultant for clients in New York and Europe.
Miller Gaffney is a graduate of the Sotheby's Institute of Art, a certified member of the Appraisers Association of America and International Society of Appraisers, auctioneer and member of the National Auctioneers Association, as well as a member of ArtTable. She founded Miller Gaffney Art Advisory in 2006 and lectures and writes on all aspects of art.