Gillian Barrett migrated to Australia as a child, with her parents. She grew up at Faulconbridge in the Blue Mountains, living in a house across the gully from Norman Lindsay (q.v.). In 1971 she graduated with a B. A. (Honours in Psychology) from the University of New South Wales and was employed as a clinical psychologist at Concord Repatriation and General Hospital in Sydney before moving to Fiji with her husband in 1972, where her two daughters were born. In 1980 she returned to Australia and settled on a farm at Newbury in the Victorian Central Highlands, where she earned a living breaking and training horses, teaching riding, and writing short stories and articles for various newspapers and magazines. In 1984 she was the Victorian correspondent for The Australian Bloodhorse Review, producing articles about breeding and training thoroughbred horses.
Barrett remarried in 1985 and moved to Moruya in N.S.W., but returned to Newbury eighteen months later and resumed her career as a psychologist, moving to Ballarat in 1989. In 1993 she married again and moved to Townsville where she continued to work as a psychologist, as well as completing a B.Litt in Journalism and an M.A. in Professional Writing and Literature, both from Deakin University.