Tashiro became Vice Chief of the 5th Section (Asian Intelligence), 2nd Bureau within the General Staff in 1926, and was considered an expert on China. He was promoted to major general in 1930, when he was given command of the IJA 27th Infantry Brigade. In 1932, he was promoted to Chief of Staff of the Shanghai Expeditionary Army.
Tashiro's career trajectory involved rising through the ranks within the military, becoming a prominent figure in Asian intelligence and eventually leading key units during the period of Japanese expansionism.