 When Saitō Yoshitatsu, a son of Dōsan, and he clashed in a fight, Michitoshi took the side of Yoshitatsu.Michitoshi later fought under Saitō Tatsuoki, the son of Yoshitatsu, against the Oda clan during the Mino campaign.After their castle was taken over by the Oda forces, Michitoshi accompanied Tatsuoki into exile.