Sontag was born on January 16, 1933, in New York City, but grew up in Tucson, Arizona and Los Angeles, California. She entered the University of California, Berkeley at the age of 15 and then transferred to the University of Chicago. She received two Masters degrees for Philosophy and English Literature from Harvard University. Before publishing her first novel in 1963, Sontag taught at various colleges and universities, at a time when women were just beginning to gain entry as educators in colleges and universities. Susan Sontag received a nomination for the National Book Award in 1964 for her book Against Interpretation. Sontag, who was also a filmmaker, became widely recognized for her play Alice in Bed in 1933. In 2000, her fiction book In America became a winner of the National Book Award for Arts and Letters. In 1975, she was diagnosed with breast cancer, and she died at the age 71 from a form of leukemia.
At the age of 17, Sontag married Philip Rieff, a lecturer in the University of Chicago, only two weeks after meeting him. They later had a son they named David in 1952. The two divorced in 1958 and Sontag went on to become romantically involved with both women and men. One of her partners was photographer Annie Leibovitz, with whom she also collaborated on her book Women in 1999. After being diagnosed with an aggressive form of cancer in 1975, Sontag continued writing books including Illness as Metaphor which touched upon myths around illnesses such as being guilty about being ill and being unproductive as one is experiencing sickness.