 Itagaki Taisuke was born into a middle-ranking "samurai" family in Tosa Domain, (present day Kōchi Prefecture), After studies in Kōchi and in Edo, he was appointed as "sobayonin" (councillor) to Tosa "daimyō" Yamauchi Toyoshige, and was in charge of accounts and military matters at the domain's Edo residence in 1861.He disagreed with the domain’s official policy of "kōbu gattai" (reconciliation between the Imperial Court and the Tokugawa shogunate), and in 1867–1868, he met with Saigō Takamori of the Satsuma Domain, and agreed to pledge Tosa's forces in the effort to overthrow the "shōgun" in the upcoming Meiji Restoration.During the Boshin War, he emerged as the principal political figure from Tosa domain as a leader of the Jinshotai assault force, and claimed a place in the new Meiji government after the Tokugawa defeat.