Born in Sakata, Yamagata to a family of tailors, Nunokawa studied at the Nippon Design Welfare College, graduating in 1967.

[1] He made his professional debut as a colorist for an Eiken subsidiary.

[1][3] He was key animator for Robotan, and he made his directorial debut in 1975 with the series Time Bokan.

[1] In 1979 Nunokawa decided to establish his own company, and founded Studio Pierrot, which in a few years got a string of successes, including Creamy Mami, Kimagure Orange Road, Naruto, YuYu Hakusho, Bleach, Tokyo Ghoul.

[2] During his career Nunokawa received various awards and honours, notably the Commissioner for Cultural Affairs Award [ja] and the Blue Ribbon Medal of Honor.