Born in Gifu Prefecture, Koyama attended Nihon University but quit midway to join the independent production company Kindai Eiga Kyokai, where he worked as an assistant director under such directors as Shindo Kaneto, Yoshimura Kozaburo, and Imai Tadashi. He made his directorial debut in 1971 with the children's film Koi no Iru Mura. His second film, Futatsu no Harmonika (1976), earned him a New Directors Citation from the Directors Guild of Japan. His 1983 film Hometown was entered into the 13th Moscow International Film Festival. His 1987 film, Hachiko Monogatari, about the faithful dog Hachiko, was the top Japanese film at the box office that year. He is known for his humanistic perspective.

Koyama was given the Chunichi Culture Award in 2000 for producing films that scrutinize the age and the region. (Source: Wikipedia)