Rossner was married three times, divorcing her first two husbands. She had two children, Daniel and Jean, with her first husband.
Rossner wrote her first novel, published years later as To The Precipice in 1966. Her initial books were not successful. Soon after leaving her husband she wrote Any Minute I Can Split (1972), about a pregnant woman who runs away to a commune.
She wrote the story but said Esquire lawyers killed the article because they felt the story would affect the pending trial. Rossner then decided to write the novelized version, Looking for Mr. Goodbar.
The book brought her fame and wealth, allowing the thirty-seven-old to quit her day job and focus full time on writing. In 1977, Rossner published Attachments, a story about a pair of friends who marry conjoined twins. Attachments was followed by Emmeline, the story of a fourteen-year-old farm girl who gets a factory job to support her impoverished family. August, her most successful post-Goodbar novel, was published in 1983 to critical acclaim.
Rossner became seriously ill with viral meningitis after August's publication. She consequently lost much of her memory and contracted diabetes. Rossner did not write for many years. She published His Little Women in 1990 to universal bad reviews. Olivia (1994) followed. Rossner published her last novel, Perfidia, in 1997.
Rossner died on August 9, 2005 at the age of seventy. She was survived by her third husband, Stanley Leff, her two children, and three grandchildren.