In 1922, Sugiyama began his rise in the Ministry of War, first as chief of the Aviation Section of the Military Affairs Bureau and then as director of the Military Affairs Bureau. In 1930, he became deputy minister of the army. Appointed army deputy chief of staff in 1934, in February 1937 he joined the cabinet of Senjuro Hayashi as army minister. He was retained in that position in the succeeding cabinet of Fumimaro Konoe. After the 7 July Marco Polo Bridge Incident, Sugiyama was among the faction that pushed for escalation of the conflict, leading to the Sino-Japanese War.
In December 1938, Sugiyama assumed command of the North China Theater. Between October 1940 and February 1944, he was army chief of staff. Although Sugiyama's career was capped by the conferment of the title of generalissimo in 1943, he did not distinguish himself for enlightened leadership. He excelled only in political maneuvering and followed the prevailing political winds within the army. Emperor Hirohito often reprimanded Sugiyama for his evasive statements and his claims that victory over China and then the United States would be easily achieved.
In July 1944, Sugiyama joined the cabinet formed by his former classmate Kuniaki Koiso, who replaced Hideki Tojo as prime minister. Sugiyama presided over the final mobilization efforts as Japan began preparations for an anticipated Allied invasion of the main islands in early 1945. He responded to the Japanese surrender by taking his own life with a pistol on 12 September 1945. Kurosawa Fumitaka
Beasley, W. G. Japanese Imperialism, 1894–1945. New York: Oxford University Press, 1984.; Boyle, John Hunter. China and Japan at War, 1937–1945. Stanford, CA: Stanford University Press, 1972.; Sanbo Honbu, ed. Sugiyama Memo. 2 vols. Tokyo: Hara Shobo, 1967.