He graduated from military academy in 1874, and served as a sergeant in the Imperial infantry during the Satsuma Rebellion of 1877.

He rose rapidly through the ranks, to sergeant-major and then was commissioned as a brevet second lieutenant by the end of the same year.

Kamio served in Qing dynasty China as a military attaché from 1885–86,[2] during which time he was promoted to captain.

After the start of World War I, Kamio, with a reputation for solid caution rather than brilliance, was selected to lead Allied ground forces in the seizure of Tsingtao from Germany.

[4] In Summer 1914, Kamio's 18th Division of 23,000 men backed by 144 guns began a bombardment of the port on 2 September 1914.