Nagao Norikage served as a bushō during the Sengoku and Azuchi-Momoyama periods.  He was the eighth head of the Shiroi-Nagao clan and served as the lord of Shiroi Castle in Kōzuke Province.

Norikage is surmised to be either the son of Nagao Akitada, the sixth head of the Sōja-Nagao clan or Nagao Akikage, the fifth head of the Takatsu-Nagao clan – an illegitimate branch of the family.  Norikage was adopted by Nagao Kagenobu, the seventh head of the Shiroi-Nagao clan.  In 1528, Kagenobu was slayed by a retainer.  After this unexpected death, Norikage, through the offices of Nagano Narimasa, became the next head of the clan.

Initially, he adopted the name of Kagefusa, but, after receiving one of the characters from the name of his lord, Uesugi Norimasa, he changed to the name of Norikage.  In 1567, owing to an invasion of Kōzuke by Takeda Shingen of Kai Province, the landholdings of the Shiroi-Nagao clan were lost while Norikage fled to the protection of Uesugi Kenshin of Echigo Province.  Thereafter, Norikage obeyed Kenshin, participating in assorted battles.  In 1569, after formation of the Etsu-Sō dōmei, an alliance between the Uesugi of Echigo and the Hōjō of Sagami, his influence on commanders in Kōzuke weakened so he returned to Shiroi Castle.

In 1572, after Shiroi Castle came under attack by Sanada Yukitaka, Norikage fled to Hassaki Castle.  Upon this event, he transferred headship of the clan to his second son and heir, Nagao Terukage.  In 1578, at the Otate Conflict, Norikage joined with Uesugi Kagetora and was defeated.  After the conflict, Norikage separated from the Uesugi clan and served Takeda Katsuyori, Takigawa Kazumasu, and the Gohōjō clan.