Ousaka began working at Anime R in 1983, an animation studio ran by Moriyasu Taniguchi. There he took part in many of Sunrise's productions. During the '80s, he became one of the big-name animators that helped shape the industry, alongside names like Hiroyuki Okiura, Kazuchika Kise and Masahiro Kase. After having left Anime R in 1991, he mainly kept working on Sunrise's works as a freelancer.
In 1998, he was involved in the establishment of Bones, a studio which he then joined as a key member. Ousaka has also been involved in productions with Kyoto Animation, which was still a sub-contracting studio at the time, where he helped train the studio's young animators.
Ousaka passed away from cancer on September 24, 2007.
