Masato Sako was a Japanese actor and voice actor born on November 9, 1946, in Iwakuni, Yamaguchi Prefecture. He passed away on January 11, 2003, at the age of 56. Sako began his career on the stage after dropping out of Chuo University and joining the theater company Gekidan Kumo, later transferring to Engekishūdan En. His early work included performances in Shakespearean plays and appearances in television dramas.

From the 1980s onward, Sako became highly active in voice acting, particularly in the dubbing of Western films and in animation. One of his notable anime roles was the title character in the long-running educational series Dotanba no Manners, which aired from 1984 to 1987. In this program, he voiced the hapless office worker Mr. Dotanba, whose frequent etiquette failures served as the basis for each episode's lesson.

Sako's filmography includes a range of other anime roles. He provided voices for Winston Geybridge in Brain Powerd and John Drinker Cope in the Legend of the Galactic Heroes OVA series. He was also a recurring presence in the long-running detective anime Case Closed, known as Detective Conan, where he voiced several characters, including the first voice of Ginshiro Toyama and roles such as Masahiro Sannai and Yoshio Sadakane. His work also extended to theatrical anime, with a role in the You're Under Arrest: The Motion Picture.

Beyond anime, Sako was highly regarded for his work in dubbing foreign films and television series, where he was frequently the Japanese voice of actor Gary Oldman. Among his many dubbing credits are the roles of Norman Stansfield in Léon: The Professional, Jean-Baptiste Emanuel Zorg in The Fifth Element, and Ivan Korshunov in Air Force One. He also dubbed performances for actors such as William H. Macy in Fargo, Robert Patrick as the T-1000 in Terminator 2: Judgment Day, and Dustin Hoffman in Hero. His work in animation dubbing included roles in Toy Story 2 as Wheezie the Penguin and in Batman: The Animated Series.

After his death from oral cancer in 2003, several other voice actors were chosen to succeed him in his ongoing roles, a common practice in the Japanese voice acting industry. His oldest daughter, Mayumi Sako, is also an actress.