Born in Tosa (now Kochi), Nakaoka, together with Sakamoto Ryoma contributed to the anti-Tokugawa movement. His major effort was the mediation between the domains Satsuma and Choshu, which led to the Satsuma-Choshu alliance of 1866 and Satsuma support for Choshu in its fights against a Tokugawa punitive expedition.

Before the fall of the Tokugawa Bakufu, Sakamoto and Nakaoka were murdered by secret police units of the Tokugawa Bakufu in Kyoto.

Nakaoka is buried in Gokoku Shrine in Kyoto, next to Sakamoto.

Statue of Sakamoto Ryoma and Nakaoka Shintaro in Kyoto

Nakaoka Shintaro, 1838-1867