Born into a Nanbu domain samurai family in Morioka, Iwate District, Mutsu Province (present-day Morioka City, Iwate Prefecture). After the Meiji Restoration, as a person from the Tohoku region while Satsuma-Choshu cliques monopolized political power, he worked his way up through difficult circumstances as an official in the Foreign Ministry and Home Ministry. Under Ito Hirobumi's support he devoted himself to strengthening the Rikken Seiyukai party's organization and in 1918 became the 26th Prime Minister. He was beloved by ordinary people as the "commoner prime minister" with no peerage. As the first party politician to become prime minister, he made a major contribution to establishing party government. Under the banner of "positive policies," he worked to improve domestic governance through railway and road improvements and expansion of higher education. On the other hand, he was unenthusiastic about universal suffrage and maintained the single-member district system to protect Seiyukai interests. He also faced difficult problems including the Siberian Intervention (1918), the Rice Riots, and the response to Korea's March First Movement. On November 4, 1921, while walking on a platform at Tokyo Station, he was stabbed and killed by Yamanote Line station worker Nakaoka Konichi. He died at 65.