Sentouin was the daughter of Nagao Tamekage and older sister of Uesugi Kenshin. She married Nagao Masakage in 1537, and they had two sons and two daughters between them. Their oldest son died at the age of 10, but their second son, Uesugi Kagekatsu, became Kenshin's adopted son and later head of the Uesugi Clan.

It is said that Sentouin was the one who recommended that Naoe Kanetsugu become Kagekatsu's attendant.