Kōichi Hashimoto is a Japanese actor, voice actor, and narrator born on January 12, 1953, in Chiba Prefecture. His real name is Yōichi Mitsuhashi. He is a graduate of Senshu University and was a member of the first training class at the Tokyo Actors Cooperative Association (Haikyo). His career began in 1974 with roles in radio dramas and dubbed foreign television shows, with his first major anime role coming in 1977 as Hisashi Gohigō in Ippatsu Kanta-kun.

Hashimoto is known for a wide range of anime roles spanning several decades. Some of his most iconic characters include Cygnus Hyoga in the original Saint Seiya television series and its subsequent films and OVAs, including The Hades Chapter - Sanctuary. He is also well-known as the voice of Genzō Wakabayashi in the original Captain Tsubasa anime. Other notable television roles include Bento Malus 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. He also took on roles in the Cream Lemon series, including Joke Tōgō and Ryūji Kōno.

Throughout his career, Hashimoto has been affiliated with several talent agencies, including Arts Vision, Aksent, and Ken Production. He is currently represented by Umikaze. Beyond anime, his work as a narrator has been featured in television programs, corporate videos, and commercials, earning awards such as the ACC award for the National TV "Koshien Monogatari" series. He has also been active as a lecturer at the Tokyo Announcement Academy, teaching and mentoring new talent in the industry.