Interested in effects animation, he cites Yoshinori Kanada and Kazuhide Tomonaga as major influences. He had his first breakthrough as animator on Space Adventure Cobra and Golgo 13: The Professional, in which his effects work and fun character animation was highly praised. Later his work became increasingly more experimental, combining his animation with intricate art design and CGI.
During his period at Annapuru he befriended Takashi Nakamura and the two worked on several projects together even after leaving the studio. Katsuhiro Ootomo recognized his talent and Morimoto became a key figure in many of his works. He debuted as Director on Robot Carnival.
In 1985 he founded Studio 4°C alongside former Ghibli producer Eiko Tanaka. He would later leave the studio in 2011.
