[1] Miyazaki first brought up Boro as a potential idea for a movie, but Ghibli producer Toshio Suzuki, concerned about the difficulty of making a feature-length film with no human characters, proposed creating Princess Mononoke instead.

[3] However, sensing that Miyazaki still wanted to work on projects, Suzuki asked the retired director if he would be interested in creating a short film using his Boro the Caterpillar idea.

[2] In 2015, Miyazaki decided to come out of retirement to work on a roughly ten-minute short film meant to be screened exclusively at the Ghibli Museum.

[2] On September 21, 2015, CG animator Yuhei Sakuragi announced that he would be helping Miyazaki complete Boro the Caterpillar.

Japanese television host and comedian Tamori provided all voices and sound effects for Boro the Caterpillar.