Kagekatsu UESUGI was born in 1555 in Echigo Province (Niigata Prefecture as it is known today) as the second son of Masakage NAGAO, who was the head of the UEDA NAGAO clan at that time.
弘治元年（1555年）、越後国（現・新潟県）に上田長尾氏当主・長尾政景の次男として生まれる。