Following Takauji ASHIKAGA who raised an army to overthrow the Shogunate in the Genko War, Mitsuyoshi participated in the attack of Rokuhara Tandai (an administrative and judicial agency in Rokuhara, Kyoto) in Kyoto.
元弘の乱で倒幕の兵を挙げた足利尊氏に従い、京都の六波羅探題攻撃に参加。