Julia McCarthy was born in Toronto in 1964. In 1987, McCarthy graduated with a bachelor's degree from the University of Waterloo. In 1988, she audited a course in Developmental Psychology from Seattle University. And between 1991 and 1994, she audited select courses in Child, Adolescent, and Adult Psychology from the University of West Georgia.

McCarthy lived in the United States of America for ten years, most notably in Alaska and Georgia where she was guest lecturer in English and Psychology at the University of West Georgia (1992). She also lived in Norway and South Africa before returning to Canada and settling in Upper Kennetcook (East Hants) and the Annapolis Valley, Nova Scotia. While in Nova Scotia, McCarthy worked as a freelance writer, teacher of creative writing, editor, and potter. As a potter, McCarthy was the owner of Mudaphors Studio (in Nova Scotia). McCarthy was married twice, first to Richard Alapeck and later to Dr. Graham Stewart.

In 2002, McCarthy published her first book Stormthrower. In 2010, she published her second book Return from Erebus for which she won the Canadian Authors Association Poetry Award in 2011. In 2017, McCarthy published her third anthology All the Names Between which was a shortlisted finalist for the Governor General's Award for English-language poetry at the 2017 Governor General's Awards and was awarded the J. M. Abraham Poetry Award (formerly the Atlantic Poetry Prize).

Julia McCarthy died in 2021.