Hiroaki Sato is a Japanese anime director, screenwriter, and original creator, primarily active from the 1980s through the 2000s. He is most widely recognized as the original creator, director, and primary screenwriter for the cyberpunk science fiction original video animation series Key the Metal Idol, which was released in 15 episodes from 1994 to 1997.

Sato's career in the animation industry began in the 1980s. He served as an assistant director and animation director on the landmark 1988 film Akira, which remains one of the most influential works in Japanese animation history. He also worked as an episode director and storyboard artist on the television series Mrs. Pepperpot, which aired from 1983 to 1984.

Following Key the Metal Idol, Sato continued to work as a screenwriter and director across several television anime series. He wrote scripts for the historical comedy series Yoshimune in 2006 and contributed screenplay and storyboard work to the romantic drama White Album in 2009. In 2001, he wrote scripts for the television series Super GALS!. He also provided the screenplay for Fushigi Yugi Eikoden, an original video animation sequel to the popular Fushigi Yugi series, released in 2001.

Across his major projects, Sato frequently held multiple key creative roles simultaneously, functioning as both series director and primary scriptwriter. His most noted work, Key the Metal Idol, stands as his singular credit as an original creator, blending themes of identity, humanity, and technology in a narrative centered on a young android seeking to become human by making friends.