Such internal discord within the Shiba clan, along with issues involving succession to the position of the heads of the Ashikaga shogunate, Hatakeyama clan, etc., led to the outbreak of the Onin War in 1467, and Takakage played an active role in the Western squad in cooperation with the master, Yoshikane SHIBA.
このような斯波氏の内訌に加え、足利将軍家や畠山氏の家督相続問題から、応仁元年（1467年）に応仁の乱が勃発すると、孝景は主家の斯波義廉と協力して西軍として活躍する。