Colleen McCullough was born at Wellington, New South Wales, and was educated at the University of Sydney. After working as a school-teacher, library assistant and journalist, she trained and worked as a neurophysiologist in Sydney, England and the United States of America between 1967 and 1976. In 1974 she published her first novel, Tim, attracting some commercial success and receiving further exposure when it was adapted to film. But with her second novel, The Thorn Birds (1977), she became an international success and saw her novel produced as a highly popular television series in 1983. In the 1990s, she wrote a series of six novels set in ancient Rome before returning to an Australian setting with Morgan's Run (2000). McCullough also wrote a cookbook Cooking with Colleen McCullough and Jean Easthope (Harper & Row, 1982) and a biography, Roden, V.C. (Random House, 1998).
McCullough's romances have been extremely popular, but they have attracted limited critical approval. Nevertheless, she won the Italian Premio Scanno for The Song of Troy (1998); and in 1993 she was awarded an honorary doctorate from Macquarie University for the meticulous research she conducted for her Roman novels.
Colleen McCullough resided on Norfolk Island from 1980. She was patron and board member of various scientific and medical organisations in Australia and overseas. In 1993 she learned she was suffering from a degenerative eye disease. This did not stop her writing and she continued to publish.