Nancy Phelan was educated at the University of Sydney and the Sydney Conservatorium of Music. She lived in England from 1938 to 1945, returning to Australia after World War II with her husband and daughter. For five years Phelan was a member of the South Pacific Commission, working and travelling in the Pacific Islands, experiences described in her book Pieces of Heaven. She travelled widely in Europe, the Middle East, Asia, South America, Japan and the USSR.
As well as the works listed on AustLit, Phelan wrote a number of travel books, including Morocco is a Lion (1982). She also wrote, either in collaboration with Michael Volin or on her own, a series of yoga guides (from Yoga for Women in 1963 to Yoga and Sex in 1977, with many titles reprinted in later years), as well as craft books including Coral as a Building Material (1952), How to Make Your Own Filmstrips (1954) and How to Make Your Own Posters (1957). In collaboration with Nina Nicolaieff she produced a series of Russian cookbooks between 1969 and 1981. Phelan published a biography of her cousin, the musician and conductor Charles Mackerras, in 1987.
Phelan befriended a number of well known artists and writers, among them Dorothy Hewett, Patrick White and Kylie Tennant (qq.v.). Three of Phelan's aunts, Louise Mack, Amy Mack and Gertrude Mack (qq.v.), were also Australian writers.
For further details about her life see her autobiography Writing Round the Edges (2003).