Shields was born in Illinois. She studied in Illinois, Ottawa, and Exeter. While on a sponsored study week in Scotland, she met her future husband, Donald Hugh Shields. In 1957, they married and moved to Canada.
In the 1970s, Shields began to work as an editorial assistant for a Canadian journal. Then she began to write novels of her own. Both she and her husband taught at the University of Manitoba during the 1980s.
Her novels were very popular in the last twenty years of her life, and she won multiple awards for writing. In 2000, she retired to Victoria in British Columbia. She died in 2003 of breast cancer.