He was a member of the House of Peers and a Professor of Law at Tokyo Imperial University.

[1] Commissioned by the Ministry of Education in 1902 he became an assistant professor at Imperial University in 1903.

From 1911-1921, he served as a Director at Prince Fumimaro Konoe's East Asia Economic Research Center (Toa Keizai Chosakyoku).

[4] The Japan Academy recognized Matsuoka for his academic achievements with the Gomontsuki Ginkabin in 1945.

Matsuoka married the former Nishikawa Yuka and had 3 children, son Yasumitsu, who would go on to be a professor at Nihon University, and two daughters.