Koichi Chiba was a Japanese voice actor and sound director born on August 13, 1931, in Iwate Prefecture, Japan. He passed away on November 9, 2001, at the age of 70. His professional name uses the kanji 千葉耕市, and he was also known by the reading Koichi Chiba using different kanji for his given name. He was a graduate of Nihon University.

Chiba's voice acting career encompassed a wide range of roles in television animation, original video animations, and theatrical films. One of his earliest roles was as Police Inspector Tawashi in the 1963 series Astro Boy, and he later voiced Dr. Hyde in the 1980 version of the series. He was known for playing various characters in the long-running Lupin the Third franchise. Other notable television roles included the school principal in Urusei Yatsura. He played the role of Sadayoshi Fujimoto in the series Kyojin no Hoshi: Shukumei no Taiketsu and voiced both the Narrator and Doctor Gulture (also known as Dr. Franken Von Vogler) in Giant Robo. His work in the Brave mecha anime series included the role of Cain in The King of Braves GaoGaiGar and Ohboss in Legendary Brave Da Garn. He also provided the narration for Legendary Armor Samurai Troopers, known in English as Ronin Warriors.

In theatrical animation, Chiba voiced Corte Gianni in Crusher Joe: The Movie and The Watchmaker in Golgo 13: The Professional. His extensive work in original video animations included the role of Professor Louie Renet in Kaze to Ki no Uta. He performed the role of Dr. Tsukuba in Love Position - The Legend of Halley, the role of Death Mask or Sigma 99 in A Time Slip of 10000 Years: Prime Rose, the role of Tarkin in Dragon Quest Saga: Emblem of Roto, and the role of Guwagoze in the film Gegege no Kitarō: Gekitotsu!! Ijigen Yōkai no Daihanran. He also voiced Dondora (Don Dracula) in Undersea Super Train: Marine Express. Other roles included Yura Treyanov in Hell Target, the Cyclist in Eko Eko Azarak II: Birth of the Wizard, Kichizo's Brother in Animated Classics of Japanese Literature, Devadatta in Ai no Senshi Rainbowman, Chiba Shūsaku and the Narrator in Akado Suzunosuke, Dr. Ruffelle in Gatchaman II, and Dr. Dogma in Seigi wo Aisuru Mono Gekkō Kamen.

Beyond his work in original Japanese animation, Chiba was highly active in dubbing foreign productions for Japanese audiences. He was known as the regular Japanese voice actor for Burgess Meredith, most famously dubbing his role as Mickey Goldmill in the Rocky film series for various television broadcasts. He also dubbed Star Wars characters including Emperor Palpatine for episodes V and VI, and was dedicated to dubbing the works of Christopher Lee and Peter Cushing.

In addition to his voice acting, Koichi Chiba had a substantial career as a sound director. He oversaw sound production for numerous anime series, including the long-running Dirty Pair franchise, Ronin Warriors, Dead Heat, and multiple entries in the Mobile Suit SD Gundam series of shorts and OVAs. He was particularly noted for his work as sound director across the Brave series, including Brave Exkaiser, The Brave Fighter of the Sun Fighbird, The Brave Fighter of Legend Da-Garn, The Brave Express Might Gaine, Brave Police J-Decker, Brave Command Dagwon, and The King of Braves GaoGaiGar.