Yōichi Mitsuhashi is the birth name of Kōichi Hashimoto, a Japanese actor and voice actor born on January 12, 1953, in Chiba Prefecture, Japan. He is a graduate of Senshu University.

His career as a voice actor began in the mid-1970s. He was a member of the first training class at the Tokyo Actors Cooperative Association and started working in radio dramas and dubbed foreign television shows around 1974. His first major anime role came in 1977 as Hisashi Gohigō in the series Ippatsu Kanta-kun.

Throughout his long career, Mitsuhashi has been affiliated with several talent agencies, including Arts Vision, Aksent, Ken Production, and Art 7. He is currently represented by Umikaze.

As a voice actor, he is known for a range of significant roles in popular anime series. He is most recognized for his portrayal of Cygnus Hyōga in the original Saint Seiya television series, as well as in its subsequent films and OVAs. He also provided the voice of Genzō Wakabayashi, the celebrated goalkeeper, in the original Captain Tsubasa anime. Other notable television roles include Bento Marusu in Space Runaway Ideon, Rod Drill in Machine Robo: Revenge of Cronos, Wilson in Ginga Nagareboshi Gin, Sley in The Super Dimension Century Orguss, and Wong Yunfat in Mobile Fighter G Gundam. In the long-running series One Piece, he has voiced the characters Captain Kuro and Sai. His other animation work includes roles in Aura Battler Dunbine, Silent Möbius, City Hunter, Future GPX Cyber Formula, Detective Conan, and Rurouni Kenshin.

Beyond his work in television animation, Mitsuhashi has also voiced characters in numerous OVAs and theatrical films. His film work includes reprising his roles in the Saint Seiya and Captain Tsubasa film series, as well as parts in Doraemon films, the Silent Möbius films, and Space Runaway Ideon: Be Invoked. He has also worked as a narrator for television programs, corporate videos, and commercials, earning awards such as an ACC award for the National TV Koshien Monogatari series.