Early interested in Western learning, Nakae studied French and Dutch as a boy and served for a while as a translator for the French minister to Japan. In 1871 he was sent abroad as a member of the Ministry of Justice and studied philosophy, history, and literature in France. On his return, he served briefly in the government and then retired and began his own French language school.

In 1881 Nakae started the influential daily newspaper, Tōyō jiyū shimbun (“Oriental Free Press”), which he used to propagate Western democratic ideas. He also served as a member of the Diet (parliament) and engaged in various business enterprises. His real fame, however, came from his popularization of Rousseau; he translated Du contrat social and then, while he lay dying of a malignancy, wrote two best-selling books in which he explained French democratic ideas to the Japanese.