He established a bekke (branch family) independently in Uwajima which was awarded to his father, Masamune, in recognition of his contribution of joining the Osaka Fuyu no Jin (Winter Siege of Osaka), and he became a kokushu-daimyo (a daimyo with his own domain).
父・政宗の大坂冬の陣参陣の功によって与えられた宇和島に別家を立て独立、国主大名となった。