Comstock began her career at the University of Minnesota as an assistant in the rhetoric department under Maria L. Sanford. She was promoted to the position of instructor in 1900 and assistant professor in 1904. She was appointed the school's first dean of women in 1907 and a full professor in 1909. In 1912 Comstock accepted an invitation to become the dean of Smith College, where she served as acting president for a period in 1917-1918. From 1921 to 1923, she served as president of American Association of University Women. On October 20, 1923, Comstock was inaugurated as president of Radcliffe College. She spent 20 years leading the school, strengthening its academic programs and, in 1943, persuaded Harvard to accept classroom coeducation. When Radcliffe celebrated its 75th anniversary in 1954, Comstock was called "the chief architect of the greatness of this college". In addition to her academic career, Comstock was appointed to the National Committee on Law Observation and Enforcement, known as the Wickersham Commission, in 1929. After her retirement from Radcliffe, Comstock remained active in academia, serving on the Smithboard of trustees, working on a graduate center for Radcliffe, and traveling extensively in support of her husband's research.
Marriage
A week after her retirement from Radcliffe in 1943, Comstock married Yale professor emeritus Wallace Notestein. They had met in Minnesota decades before, but Comstock had focused on her academic career, as her father wished. Neither had married in the intervening years. Notestein died in 1969.
Death and legacy
Ada Comstock Notestein died of congestive heart failure at her home in New Haven, Connecticut, on December 12, 1973. The largest collection of her papers, the Ada Louise Comstock Papers, 1897–1950, are housed at the Smith College Archives. Comstock's name has been honored with buildings on college and university campuses, including Comstock Hall at the University of Minnesota, Comstock Hall in the Radcliffe Quad, and Comstock House residence hall at Smith College. Her full name has also been used for the title of Smith college's program for non-traditional students, as well as for a lecture series. Her childhood home is maintained as a historic site by the City of Moorhead and the Minnesota Historical Society.