Takeharu Onishi is a Japanese voice actor and stage actor born on July 8, 1967, in Nara Prefecture, Japan. He is affiliated with the talent agency Arts Vision and is a founding member of the theater company Akapera, also known as Acapella Club. Onishi, who speaks the Kansai dialect, trained at the Katsuta Voice Acting Academy.

Onishi's career, which began in the 1990s, encompasses a wide range of roles in anime, video games, and dubbing for foreign films. His voice work includes several of the specific roles mentioned, such as Knoll in Fortune Quest L (1997), Father in Ai no Wakakusayama Monogatari (1999), Tom Yunk in Heat Guy J (2002), and Ametaro and Hanatare-kun in the Pururun! Shizuku-chan series. He is also known for his performances as Tetsuya Murata in Gintama, the shinigami Gook in Death Note, Worm in Hunter X Hunter, and Madarao in Kekkaishi.

Beyond these roles, Onishi has been a consistent presence in long-running franchises, providing voices for numerous characters in series such as Crayon Shin-chan, Detective Conan, and Pokémon. His work also extends to film dubbing, where he is notably the regular Japanese voice for Jon Favreau's character Happy Hogan in the Marvel Cinematic Universe. In the realm of video games, he is recognized as the voice of Tingle in several The Legend of Zelda games and as Augustus Cole in the Gears of War series.

A notable achievement in his personal life, which garnered public attention, was his marriage to fellow voice actress Masayo Kurata in 2021.