Ōkubo was a "samurai" of the Satsuma Domain and joined the movement to overthrow the ruling Tokugawa Shogunate during the "Bakumatsu" period. Upon the founding of the new Empire of Japan, Ōkubo became a leading member of the Meiji Restoration and a prominent member of the Meiji oligarchy. Following his return from the Iwakura Mission in 1873, he became Lord of Home Affairs and used his office's authority to rapidly expand his influence within the Restoration government. By the beginning of 1874, he had firmly established himself as the country's "de facto" dictator. In this capacity, he enacted numerous structural reforms, pacified disputes within the Meiji regime at the Osaka Conference of 1875, and suppressed several rebellions threatening the survival of the empire. As a result of his oppressive leadership, Ōkubo became the focus of deep animosity within Japan and was ultimately assassinated in 1878.