On June 1, 1861, Tadanori returned to the head family changing his name to Hisamitsu (at the same time he also changed his common name to Izumi), and he came to be treated as the 'the father of province' and grasped the real power of the domain administration.
文久元年（1861年）4月23日に宗家へ復帰し、諱を久光と改名（同時に通称も和泉に改める）、「国父」として遇されることになり、藩政の実権を掌握する。