Takeshi Ōbayashi was born in Okayama Prefecture in 1942. He is affiliated with the talent agency Production Tank and also serves as the Chairman of the Japan Film Actors Association. While his career spans decades across film, television, and stage, his work in voice acting and live-action character roles has established him as a recognizable presence in Japanese entertainment.

Ōbayashi's career began after training as an actor, and his early work included a significant role in the 1970s live-action television drama Suikoden. His voice acting credits include the anime film Kuroi Ame ni Utarete, where he voiced the character Iwata Takeshi (the same name as the actor is sometimes used in credits for this role). In the realm of science fiction, he is known for providing the voice of Schultz in the classic anime series Space Battleship Yamato.

In live-action cinema, Ōbayashi has appeared in numerous films, including Shin Godzilla, in which he played the supporting role of Shuichi Kunihira. He also appeared in the film South Pole Story and had a recurring role in the Ultraman franchise as Black Commander in Ultraman Leo. On television, he has made guest appearances in a wide array of popular dramas, including the asadora Hanako and Anne, the medical drama Dr. Koto's Clinic, the police drama Partners (Aibo), and the science fiction thriller Mr. Brain.

He is also known for his stage work, having performed in productions such as Run For Your Wife and喝采 (Kassai). Information regarding recurring anime-specific voice acting collaborations remains sparse.