Sakai clan
Born in 1641, he was the eldest son of Kira Yoshifuyu. His mother was a member of the high-ranking Sakai clan. On the death of his father in 1668, Yoshinaka became the 17th head of the household, inheriting lands evaluated at 4200 "koku". His wife was from the Uesugi clan, and his eldest son was adopted by Uesugi Tsunakatsu, the head of the Dewa Yonezawa "han", taking the name Tsunanori. Yoshinaka named his second son as his heir, but when that heir died, Yoshinaka adopted Tsunanori's second son, strengthening the connection between the Kira and the Uesugi.