Joan Brady was born on 4 December 1939 in San Francisco, California, USA, daugther to Mildred Edie Brady and Robert A. Brady. She has one sister, Judy. She was a dancer with the San Francisco Ballet and the New York City Ballet, a story she tells in her highly-acclaimed autobiography The Unmaking of a Dancer. Then she went on to study philosophy at Columbia University in New York. In 1963, she married author Dexter Masters, her mother's secret lover. Together they had a son, Alexander Masters, who authored Stuart, A Life Backwards.
She currently lives in Oxford, England. She was the first woman to win the Whitbread Book of the Year Award (now Costa) with Theory of War, she is also the author of short stories, articles, reviews, and suspense novels.