Gabrielle Lord was born in Sydney. She was educated at the Sacre Coeur Convent, Rose Bay, and the University of New England where she earned an honours degree in arts. Lord began writing fiction while working for the Commonwealth Employment Service.
In 1977 she won a grant from the Literature Board to finish her first novel, but a devastating reader's report caused her to abandon that novel and write another in just three weeks. That novel, Fortress, was published in 1980, initiating Lord's series of thriller-mystery novels. Most of Lord's novels are set in contemporary Australia and deal with the abuse of children and the harm inflicted by families. To achieve authenticity in these novels, Lord has conducted extensive research into crime investigation techniques, attracting a loyal group of readers to her tightly-plotted and fast-paced narratives.
Several of Lord's novels have been produced as films, and when the film rights to her novel Salt (1990) were sold, she was free to write full-time. She has since written for film and television and co-authored an account of her convent education.