[2] While in school, he began making films independently, with Kuraku naru made matenai!

[3] His script "Orenji rōdo kyūkō" won the 3rd Kido Award for screenplays in 1977, and the next year he was able to film that in his professional debut.

He has worked in a variety of genres, including suspense films, musicals, and most famously abroad, several contributions to the Heisei Godzilla series.

[3] Ōmori also participated in the formation of Director's Company in 1982, an independent production company founded by nine directors, including Kiyoshi Kurosawa, Sōgo Ishii, Shinji Sōmai, and Kazuhiko Hasegawa.

Ōmori died from acute myeloid leukemia on 12 November 2022, at the age of 70.