At the Kanno Disturbance which was developed from internal conflict of the Ashikaga family to fight between Takauji ASHIKAGA, Seii taishogun (literally, "great general who subdues the barbarians") and Tadayoshi ASHIKAGA, a younger brother of Takauji, Sadayo and his father joined to the Shogun group.
足利家内部の対立から征夷大将軍の足利尊氏と弟の足利直義の両派の抗争へ発展した観応の擾乱においては、父とともに将軍側に属する。