Mair served as Assistant Secretary-General in the office of the United Nations Secretary in 1979, from which she performed the role of Secretary-General for the World Conference of the United Nations Decade for Women held in 1980 in Copenhagen. From 1981 to 1982, she served as special advisor to the United Nations Children's Fund (UNICEF) on Women's Development at the level of assistant secretary general. She then went on to serve as Secretary-General of the United Nations Conference on Palestine from 1982 to 1987. In March 1982, Mair was appointed as Under Secretary General of the United Nations, becoming the first woman ever to hold such a title. She was the Permanent Representative of Jamaica to the United Nations from 1992 to 1995 and was also Ambassador to Cuba.
