Later, when the Kanno Disturbance broke out, Sadaie supported Tadayoshi side and conquered Oshu Kanrei (Shogunal deputy of the northern regions) Kuniuji HATAKEYAMA who took part in Takauji side, but Taga-jo Castle was attacked and defeated by Akinobu KITABATAKE of the Southern Court, who extended his power during the opportunity.
その後、観応の擾乱が勃発すると直義方に属し、同じく奥州管領で尊氏方に与した畠山国氏(奥州管領)を攻め滅ぼすが、その隙に勢力を伸張してきた南朝の北畠顕信に多賀城を攻め落とされる。