Although he had sided with the sixth Shogun, Yoshinori ASHIKAGA, he fled without resistance during the Kakitsu Incident in 1441 when Mitsusuke AKAMATSU assassinated Yoshinori and started a war in the Province of Harima, nevertheless, he then led the main punitive force, defeating Mitsusuke and gaining the Akamatsu's domains, including Harima, to become the Shugo of eight provinces.
1441年(嘉吉元)に赤松満祐らが6代将軍足利義教を殺害し、領国の播磨国で挙兵した嘉吉の乱では義教と同席していたが抵抗せずに脱出し、討伐軍の主力を率いて戦い鎮圧に貢献し、赤松氏の領国を加えて播磨国など8ヶ国の守護職を回復して再び権勢を得た。