Rintaro is the professional pseudonym of Shigeyuki Hayashi, a Japanese animation director and a co-founder of the renowned studio Madhouse. Born in Tokyo on January 22, 1941, he began his career in the animation industry at age seventeen as an in-between animator on Toei Animation's 1958 film Hakujaden, the first color feature-length anime. He later joined Mushi Productions, the studio of manga pioneer Osamu Tezuka, where he worked on seminal television series such as Astro Boy and Kimba the White Lion. Rintaro's first credited directing job was an episode of the 1963 Astro Boy series.

As a director, Rintaro is known for a career that bridges the early era of television anime with ambitious theatrical productions. His work is frequently characterized by science fiction themes and epic, cinematic spectacles, often depicting life-and-death struggles against fantastical backdrops. One of his most significant early successes was directing the 1979 film Galaxy Express 999, an adaptation of Leiji Matsumoto's manga that became a major box office hit and established him as a leading figure in anime filmmaking. He continued to direct acclaimed feature films throughout the 1980s, including Harmagedon (1983), The Dagger of Kamui (1985), and the Karma Chapter of Osamu Tezuka's Phoenix (1986).

In 2001, Rintaro directed Metropolis, a landmark film that adapted Osamu Tezuka's manga of the same name. For this project, he collaborated with screenwriter Katsuhiro Otomo, the director of Akira, to create a visually stunning retro-futuristic world that sought to communicate Tezuka's creative spirit while exploring themes of human identity and social division. The film received international acclaim and a nomination for Best Film at the 2001 Sitges Film Festival.

Rintaro's first full-length computer-generated animation was the 2009 film Yona Yona Penguin, a Japanese-French co-production produced by Madhouse in collaboration with Denis Friedman Productions. This fantasy comedy adventure, about three children who travel to a magical land, was notable for being Madhouse's first fully 3D CGI feature. In 2023, he returned to directing with a short film, Yamanaka Sadao ni Sasageru Manga Eiga 'Nezumikozō Jirokichi', which premiered at the Niigata International Animation Festival. In 2025, he was awarded the prestigious Tezuka Osamu Cultural Prize for his semi-autobiographical manga, 1-Byo 24-Koma no Boku no Jinsei.

Rintaro has also worked under the name Kuruma Hino and is a founding member of the Japanese Animation Creators Association. His career reflects a significant era of transformation for anime, from a niche interest to an internationally recognized commercial medium, with his films serving as key examples of this transnational evolution.