 He first succeeded to his father, taking the name Tōyama Kageharu (common name Rokurōzaemon); then he succeeded to his mother's birth family under the name Miyake Yaheiji, and then, marrying one of Akechi Mitsuhide's daughters, took the name Akechi Hidemitsu.Following his marriage to Akechi Mitsuhide's daughter (who had been formerly married to Araki Murashige), Hidemitsu was deeply trusted by his master, and served in the vanguard of the Akechi armies frequently.He led the attack on Battle of Honnō-ji which killed Oda Nobunaga, and became a legend for his rapid crossing of Lake Biwa to get from Otsu to Sakamoto on horseback after the loss of Battle of Yamazaki and the death of Mitsuhide.