Lerner was born Gerda Kronstein in Vienna, Austria on April 30, 1920, the first child of Ilona and Robert Kronstein, an affluent Jewish couple. Her father was a pharmacist, her mother an artist. Following the Anschluss, Kronstein joined the anti-Nazi resistance, and spent six weeks, including her eighteenth birthday, in an Austrian jail. Her family was able to escape from Austria and persecution by the Nazis; Kronstein, with the help of a young socialist lover, Bobby Jensen, immigrated to the United States in 1939.

After working a series of jobs and marrying and divorcing Jensen, she met and married Carl Lerner, a young theatre director who was active with the Communist Party USA (CPUSA). Lerner began her higher education while in her 40s, when her own children were in college, earning an A.B. from the New School for Social Research in 1963 and an M.A. and Ph.D. from Columbia University in 1965 and 1966. The Lerners subsequently moved to Los Angeles, where Carl went to work in the film industry and went on to become a successful filmmaker. The Lerners would remain together until Carl’s death in 1976.

Lerner became increasingly involved in progressive causes and joined the CPUSA in 1946, though she did not publicly acknowledge her membership until 1982. The Lerners remained active in the party during the repressive years of the McCarthy era. Lerner was a highly influential recruit to the Congress of American Women, a women's group concerned with economic and social issues.

American Women Historians, 1700s-1990s: A Biographical Dictionary, Jennifer Scanlon and Shaaron Cosner. Westport, Connecticut, and London: Greenwood Press, 1996. (Pages 144-146.)

Fifty Jewish Women Who Changed the World, Deborah G. Felder and Diana Rosen. New York: Citadel Press (Kensington Publishing), 2003. (Pages 216-220.)

Red Feminism: American Communism and the Making of Women's Liberation, Kate Weigand. Baltimore and London: Johns Hopkins University Press, 2001. (Multiple references, indexed.)

Musical

• Singing of Women (1951, with Eve Merriam)

Screenplays

• Prayer Pilgrimage for Freedom (1957)
• Black Like Me (1964)
• Home for Easter (n.d.)

Books

• No Farewell (1955) an autobiographical novel
• The Grimké Sisters from South Carolina: Rebels against Authority (1967)
• The Woman in American History [ed.] (1971)
• Black Women in White America: A Documentary History (1972)
• The Female Experience: An American Documentary (1976)
• A Death of One's Own (1978/2006)
• The Majority Finds Its Past: Placing Women in History (1979)
• Teaching Women's History (1981)
• Women's Diaries of the Westward Journey (1982)
• The Creation of Patriarchy (1986)
• Why History Matters (1997)
• The Creation of Feminist Consciousness (1993)
• Scholarship in Women's History Rediscovered & New (1994)
• Fireweed: A Political Autobiography (2003)