In December 2019, the film was announced to be 15% complete after three-and-a-half years of work. Producer Toshio Suzuki explained that Hayao Miyazaki, in the past, would be able to direct seven to ten minutes of animation per month, and they had scheduled five minutes of animation per month or about one hour per year on the film. However, Miyazaki was directing only about one minute of animation per month.
The first animated film in history to open the Toronto International Film Festival.
According to producer Toshio Suzuki, The Boy and the Heron is the most expensive film ever produced in Japan.
Hayao Miyazaki originally hoped to finish and release the film in the summer of 2020 to coincide with the Summer Olympics in Tokyo, Japan, which were postponed until 2021 due to the COVID-19 pandemic.