Born Adele Smithline and by the time she turned 21 she began studies in fashion at Pratt Institute. Simpson took over for her older sister Anna, as head designer for Ben Gershel, a 7th Avenue ready-to-wear fashion house. After running the busines for a while she began work for Mary Lee, another business on 7th Avenue in New York which she eventually purchased and renamed her namesake in 1949. The fashion brand grew and Adele dipped into jewelry though it was simply to compliment her French Couture clothing designs. Simpson continued to design into her 70s and retired in 1985 when Joan Raines, her daughter, and her son-in-law, Richard Raines, took over the business. Eventually they sold to Barron Peters in 1991.