Di Morrissey grew up in Pittwater, north of Sydney. After training as a journalist, she worked as a women's editor in Fleet Street, London. Following her marriage to an American diplomat she lived in Singapore, Thailand, Japan, Indonesia, Guyana and the United States, and she has worked as an advertising copywriter, TV presenter, screenwriter and radio broadcaster. She has also acted on stage and on television. She returned to live in Australia to work in television and was a television presenter on the original breakfast current affairs program, 'Good Morning Australia' from 1981 to 1988. She has made her living by writing since she was a teenager and has been involved with film and television as a writer, director and producer. She was commisioned to write her first novel in 1989 (Heart of the Dreaming, 1991) and has continued to publish a novel a year for Pan Macmillan. Her books have been translated into seven languages. As well as her writing, she is active on many boards and organisations.
Morrissey's novels have been inspired by specific Australian landscapes and deal with themes such as reconciliation, environment, identity, family and cultural heritage. She is known for writing popular fiction set against a well-researched background.
Morrissey is the niece of artist Pauline Jonach. Jonach prepared the artwork for Morrissey's 2004 novel, The Reef.
In 2017, Morrissey was inducted into the Australian Book Industry Awards Hall of Fame, and presented with the Lloyd O'Neill Award for Services to the Australian Book Industry.