Born in Kanagawa, Japan, in 1978. He worked in the film industry for a few years before entering the graduate film programme at the Tokyo University of the Arts. His graduation film, Passion (2008), was screened at San Sebastian Film Festival. Hamaguchi made, among others, the features Happy Hour (2015), special mention at Locarno Film Festival, and Asako I & II (2018). He also wrote the screenplay for Kiyoshi Kurosawa’s Wife of a Spy, which won the Silver Lion at Venice in 2020.