Norimasa was the son of Uesugi Norifusa and the head of the Yamauchi branch of the Uesugi and struggled to contain the expansion of the Hôjô. He joined Uesugi Tomosada of the Ogigayatsu-Uesugi in defeat at Kawagoe (1545) and in 1551 lost Hirai castle in Kôzuke province. He fled to Echigo and sought the protection of his vassal Nagao Kagetora. Kagetora readily took Norimasa into his care and was later officially adopted by him. Norimasa was later given land in Kôzuke but after Kenshin's death Norimasa supported Uesugi Kagetora in the latter's civil war with Uesugi Kagekatsu. Norimasa was killed following Kagetora's defeat.
- Initial text from Sengoku Biographical Dictionary (Samurai-Archives.com) FWSeal & CEWest, 2005