Tetsuo Sakaguchi is a Japanese voice actor, actor, and narrator born on October 24, 1952, in Osaka, Japan. He is affiliated with the talent management firm Aoni Production. A graduate of the Nihon University College of Art, where he studied theater, Sakaguchi's interest in performance began on the stage, where he was a member of several theater companies, including GAYA and Kai, before transitioning to voice acting. His background in theater contributed to his versatile vocal skills and his ability to bring a wide range of characters to life. He is known for being able to perform in the Osaka dialect, a skill that adds authenticity to characters from that region.

Sakaguchi's voice acting career, which began in the 1980s, includes roles in numerous anime television series, original video animations (OVAs), and animated films. In television anime, he has voiced a wide array of characters, demonstrating his range. Some of his roles include the村长 (village headman) in Mashin Hero Wataru, a thief in Kiteretsu Daihyakka, and the character Kumo-Otoko in Kenyū Densetsu Yaiba. He portrayed Dr. Zulowski in Shinken Densetsu Tight Road and took on roles such as a police officer and a taxi driver in Burst Angel. His work in the 2000s includes roles like Saikaku Ihara in Samurai Champloo, an attendee in Death Note, and a guest in Doraemon. He has also had multiple guest roles in the long-running series Case Closed (Detective Conan), appearing as different characters over the years. More recently, he voiced roles such as the character Hyouzou in the One Piece Log: Fish-Man Island Saga, and has been part of the cast for the series The Baby-headed Boss, playing the role of Chief Sakai.

Sakaguchi has also been active in OVAs and animated films. He voiced Keisuke Yamanami in Hijikata Toshizo: Shiro no Kiseki and provided the voice for a voice in the Memories film anthology. His involvement in the Gundam franchise includes roles such as Chairman Mashita in the Gundam Build Fighters TV series and its OVA sequel, Gundam Build Fighters: GM's Counterattack, where he played Mikio Mashita. He also performed the role of the萝卜的扮演者 (Daikon actor) in the Soreike! Anpanman film, Tobase! Kibō no Handkerchief.

Beyond animation, his career extends to video games, where he has contributed to popular franchises such as the Tales series, voicing Remiel in Tales of Symphonia, and the Yakuza series. He has also been active in dubbing foreign films and television series into Japanese, lending his voice to projects such as Home Alone and GoldenEye. In live-action, he has appeared in tokusatsu series like Kamen Rider Kuuga.

In addition to character roles, Sakaguchi is a prominent narrator. His voice has been featured in numerous television programs, including variety shows and documentaries for broadcasters like NHK, where his narration adds both warmth and authority. He is also known for his iconic ceremonial narration in popular Japanese variety shows such as Tonneruzu no Minasan no Okagedeshita. Throughout his long and varied career, Sakaguchi has been regarded as a reliable and talented supporting actor, often bringing memorable qualities to his characters and earning the trust of major production companies.