Sontag was born on January 16, 1933 in New York City. She grew up in Tucson, Arizona and Los Angeles, California. A serious and precocious child, Sontag began to read when she was three and wrote her first stories and plays at age seven. Her interest in literature and philosophy began early in childhood.

Sontag finished high school at fifteen and enrolled at University of California, Berkeley for one year. She continued college at the University of Chicago, placing out of most courses and graduating at age seventeen. That same year she married Philip Rieff, a sociology professor at the University of Chicago, only two weeks after meeting him. She followed Rieff to Harvard, where she earned masters degrees in literature and philosophy.

At age nineteen Sontag gave birth to her son, David, who was to be her only child. After eight years, her marriage to Rieff ended...