He served as a bureaucrat in the tax offices of Nagasaki, Fukuoka and Kumamoto before he was hired by the zaibatsu, Suzuki Shōten in 1908.

Kanemitsu was subsequently also president of Ōji Electric Tram Company and vice-chairman of the Japan Chamber of Commerce and Industry.

The same year, he formed his own political faction (together with Takeru Inukai), supporting Fumimaro Konoe's Shintaisei movement, and facilitated meetings with General Akira Mutō of the Imperial Japanese Army General Staff to ensure military support for the movement.

Following the end of World War II, Kanemitsu joined the Nihon Shimpotō political party, but was unable to run for office as he had been purged by the Supreme Commander of the Allied Powers along with all other government officials and ranking members of the Taisei Yokusankai, so he had his son run in his place.

He was able to resume his seat in the Lower House following the 1953 General Election after the end of the occupation of Japan as a member of the Liberal Party.