He was born in Takamatsu, Kagawa County (Takamatsu City, Kagawa Prefecture) as the first son of Katsusada (Chikuran) NAGAO of Takamatsu Domain, Sanuki Province.
讃岐国高松藩の長尾勝貞（竹嬾）の長子として香川郡高松（香川県高松市）に生まれる。