Nagao Shigekage served as a bushō during the mid to late Muromachi period.

Shigekage was the fifth head of the Echigo-Nagao clan and the deputy military governor of Echigo.  He was the great-great-grandchild (fourth-generation descendant​) of Uesugi Norimasa, the father of Nagao Yoshikage, the grandfather of Nagao Tamekage and great-grandfather of Nagao Kagetora (later known as Uesugi Kenshin).

In 1425, Shigekage was born as the son of Nagao Yorikage.  Yorikage and Shigekage (father and son) were originally members of a cadet family of the Echigo-Nagao clan, but after Uesugi Fusasada (the military governor of Echigo) eliminated Nagao Kunikage and Nagao Sanekage (father and son) who were lineal heirs of the Echigo-Nagao clan, Yorikage and Shigekage were elevated to deputy military governors.

After becoming the deputy military governor, Shigekage served Fusasada, deployed to the Kantō, and made contributions on the battlefield.  In 1467, after Uesugi Akisada (the second son of Fusasada) became the deputy shōgun for the Kantō, Shigekage joined Fusasada in striving for reconciliation between the Koga kubō and the Muromachi bakufu.  This was achieved in 1482 with a settlement known as the tohi gattai, an alliance between the central authorities in the capital of Kyōto and the Koga kubō in the Kantō.

Shigekage died on 2/25 of 1482 and was succeeded by his son, Nagao Yoshikage.