Annette Kar Baxter was born in New York City and attended New York University for a year before transferring to Barnard College. She received her B.A. from Barnard in 1947, and went on to earn an M.A. from Smith College in 1948 and another M.A. from Radcliffe College in 1949. She then began her life-long teaching career at Barnard, rising to become a full professor in 1971. In 1955, she married James E. Baxter, a psychiatrist, with whom she had two children. She received her Ph.D. from Brown in 1958. In 1975, she was one of only a handful of women to be awarded an endowed chair, named for Adolph and Effie Ochs of The New York Times.
She was a pioneer in the field of women's studies, teaching one of the earliest women's history classes in 1966 and played a key role in the creation and expansion of the Women's Center at Barnard. She became chair of the American Studies department in 1967, and served as chair of the History Department from 1974 to 1983.
In addition to her career at Barnard, she was involved in many other organizations. She was a consultant for the National Endowment for the Humanities, the Ford Foundation, and the National Council of Women. She was the author of numerous book reviews and articles, and editor of several series on women's autobiographies and women's studies. Her books include To Be a Woman in America, 1850-1930; Inwood House, 1839-1980; and Henry Miller, Expatriate. She died in a fire in 1983, at the age of 56.