Nobunao was the son of Ishikawa (Nanbu) Takanobu and the adopted son of Nanbu Harumasa (Takanobu's brother). When Harumasa's son Harutsugu died in 1582, Nobunao was named the head of the family. He submitted to Toyotomi Hideyoshi in 1590 by sending 100 horses and 50 hawks as tribute. He helped defeat Kunoe Masazane, the last independent Japanese daimyô, in early 1591. He began work on Morioka castle in 1597.
- Initial text from Sengoku Biographical Dictionary (Samurai-Archives.com) FWSeal & CEWest, 2005