The son of a Baptist minister, Parshley was educated at Harvard University. From 1911 to 1914 he taught zoology at the University of Maine. In 1917, Parshley became assistant professor of zoology at Smith College, where he would stay until 1952. In 1949 he was asked to translate Simone de Beauvoir's Le Deuxième Sexe. Despite a minor heart attack in 1952, Parshley completed this task: his translation, published in 1953, has subsequently been criticised for inaccuracies and excisions.