Historically: Son of Nagao Akikage, he became head of the Sousha-Nagao Clan at a young age. He later (around 1545) passed the position to his younger brother Nagao Kagefusa. When the clan was destroyed by Takeda Shingen and their territory lost, the family escaped into Echigo. There Kagefusa became a monk, and Kagetaka was adopted by Naoe Sanetsuna when he married Sanetsuna's daughter, Osen-no-Kata. He succeeded his adopted father as master of Yoita Castle in 1577 and was a vassal of Uesugi Kenshin. He promptly took the side of Uesugi Kagekatsu during the war for succession after Kenshin's death and mobilized the members of the Naoe Clan at the castle to subdue Kagetora's troops.
After the intra-house war and Kagekatsu's victory, a question of reward was called into question. Yasuda Akimoto, one of Kagekatsu's trusted commanders, had promised rewards to Shibata Shigeie, Mouri Hidehiro, and others to convince them to join Kagekatsu's side. However, Yamazaki Hidenori, Naoe, and others objected, for they had risked life and limb at Kasugayama Castle from the very beginning of the battle, while Shibata Shigeie and the others had been lured by promise of reward from Yasuda Akimoto.
Yasuda Akimoto committed suicide when he could not keep his promise of reward. Later, Mouri Hidehiro, carrying a grudge for his death, murdered Yamazaki Hidenori at Kasugayama Castle; Naoe, who was with him at the time and took up a sword to defend himself, was killed as well. His death ended the Naoe line, which Kagekatsu later resurrected by marrying Naoe's widow, Osen-no-Kata to Higuchi Kanetsugu and commanding him to take the Naoe name.
In Mirage of Blaze: According to Kousaka Danjou, and Houjou Ujiteru he was the ringleader of Uesugi Kagekatsu's forces in the Otate no Ran. He is now Uesugi Kagetora's protector and one of the Yasha-shuu under his command. He alone, as Kagetora's protector, was given the power to perform kanshou on other souls, a power he used to force Kagetora's soul into Minako's body.