Rubinstein was an early and avid reader, and it was the wish to write for her own children that launched her successful career as a writer for children and young adults. During her teens her parents lived in Nigeria, and Rubinstein's time was divided between boarding school in England, an English 'foster' family, and visiting her own parents. Her parents' separation when she was in her teens and her unhappy time at boarding school at that time caused her intense pain and anger, emotions she still draws on for her books.
After receiving a degree in modern languages at Oxford University, Rubinstein worked in television, publishing and as a freelance journalist. She travelled extensively and migrated to Australia in 1973.
Her first novel, Space Demons (1986), was not only highly successful commercially (spending two years on Australian best-seller lists) but also won a number of awards, including the first National Children's Peace Literature Award (1987), National Children's Book Award in the Festival Awards for Literature (1988), the Children's Book Council of Australia Honour Book Award (1987) and the YABBA award in 1990. It has also been translated and published internationally, and adapted for the theatre. Unlike many successful first-time authors, Rubinstein garnered fresh praise for her second novel Answers to Brut (1988), which won the NSW Premier's Award for Children's Literature, 1988 and was a CBCA Honour Book in 1989. Her novels since then have continued to win awards, including the CBCA Book of the Year Award in 1995 for Foxspell (1994).
In 2002 she adopted the pseudonym 'Lian Hearn' to write her fantasy works, the Otori trilogy.