Although he was following his father, Mitsuyasu, who was residing in Akechi-jo Castle as a koken (guardian) of Mitsuhide, the Castle fell in 1556 when it was attacked by Yoshitatsu SAITO for siding with Dosan SAITO, who lost the fight to Yoshitatsu SAITO.
明智嫡流だった光秀の後見として明智城(可児市)にいた父・光安に従っていたが、1556年（弘治(日本)2年）斎藤道三と斎藤義龍の争いに敗北した道三方に加担したため、義龍方に攻められ落城する。