Affiliated with Studio Khara at the time of his passing.
After some time with Studio Giants at the beginning of his career in the early '80s, he went freelance. In 1984, he served as an assistant animation director on Macross: Do You Remember Love?. During the film's production, he met Hideaki Anno, who had just moved to Tokyo. Masuo and Anno quickly became friends and established Studio Graviton together with their fellow colleagues Katsuhiko Nishijima and Kouji Itou. At Graviton, Masuo came to the limelight as the mechanical animation director on Project A-Ko.
After Graviton, he moved to Gainax, where he worked as an assistant director for Royal Space Force, and as a unit director on Gunbuster. Through the '90s and early '00s, Masuo served as a key staff member in many of Gainax's works until moving to Studio Khara in 2006.
He passed away from an undisclosed illness on July 24, 2017.
