Rintaro is the professional pseudonym of Shigeyuki Hayashi, a Japanese director, animator, and screenwriter born in Tokyo on January 22, 1941. He is recognized as a significant figure in the animation industry, with a career that began in its early days and has continued for over six decades.

Rintaro entered the animation field at the age of seventeen, working as an in-between animator on the 1958 Toei Animation film Hakujaden, which was Japan's first color feature-length anime. Following this, he moved to Mushi Production, the studio founded by the legendary manga artist Osamu Tezuka. It was at Mushi Production that Rintaro gained foundational experience working on landmark television series, including Astro Boy and Kimba the White Lion, and he received his first directorial credit for an episode of the 1963 Astro Boy series.

After leaving Mushi Production in 1971, Rintaro became a freelance director. The following year, he co-founded the acclaimed animation studio Madhouse, although he has never been an exclusive employee of the company and continues to work with various studios. He is also a founding member of the Japanese Animation Creators Association, a labor group advocating for professionals in the industry.

Rintaro has directed a wide array of feature films, original video animations, and television series. One of his earliest major successes was directing the 1979 feature film Galaxy Express 999, based on the manga by Leiji Matsumoto. He continued to helm critically admired projects throughout the 1980s and 1990s, such as Harmagedon (1983), The Dagger of Kamui (1985), and an adaptation of the popular manga X (1996). In 2001, he directed Metropolis, a film based on Osamu Tezuka's manga of the same name. Rintaro stated that with this project, he wanted to communicate Tezuka's spirit, and the film was nominated for Best Film at the 2001 Festival de Cine de Sitges.

The user provided Yona Yona Penguin as an example of his work. Released in 2009, this film marked Rintaro's first full-length feature to use computer-generated animation, telling a fantasy adventure story for a family audience. Later in his career, Rintaro returned to directing with the 2023 silent short film Yamanaka Sadao ni Sasageru Manga Eiga 'Nezumikozō Jirokichi'. Beyond directing, he has contributed to academia as a visiting professor at Kyoto Seika University, where he lectures on animation history.

Rintaro has publicly cited a wide range of influences on his work, including science fiction, American westerns, gangster films, film noir, and French cinema. Throughout his career, he has been closely associated with adapting and honoring the legacy of Osamu Tezuka, having worked on Tezuka's series early in his career and later bringing Tezuka's manga Metropolis to the screen. His role as a co-founder of Madhouse and his sustained creative output over multiple generations of anime have established him as a respected and influential figure in the industry.