Born in Choshu domain, he, after being released from house arrest, opened a private school, Shoka Sonjuku to teach the youth military arts and politics.
Takasugi joined the famous private school of the military teacherYoshidaShoin (Shoka Sonjuku), which produced almost a dozen of Japan’s political leaders of the Meiji-era, e.g.
Takasugi devoted himself to the modernization of Chōshū's military, and with his companion Kusaka Genzui, he became a favorite student of Yoshida.
Within Chōshū, Takasugi - in spite of his young age - was an influential factor and well-known as one of the most extreme advocates of a policy of seclusion and expelling the foreigners from Japan.