Born in Shimonoseki City, Yamaguchi Prefecture, Japan.
After graduating the Commercial Design Department (currently called: Visual Communication Design Department) at Musashino Art University, Tokyo, in 1975, Nishimoto worked as the Reserch Assistant of Imagery Course at the same Department until the term expired in 1981. Since then, he has been working on various animation as a freelance animator.
Also, since 1985, he has been involved in animation education as the lecturer at Musashino Art University. In 2005, he was installed as Professor of the University.