Isao Sakuma is a Japanese voice actor and narrator born in Tokyo, Japan, on September 26, 1942. A graduate of Rikkyo University, he was previously affiliated with the talent agencies Theater Echo, Sigma Seven, and Dojinsha Production.

Sakuma built a prolific career in voice acting from the 1960s onward, with many of his roles involving narration and announcements. Among his notable roles, he performed as the Marathon Announcer in the 1974 live-action film Lupin III: Strange Psycho-Kinetic Strategy. He also appeared in the Lupin III television series, contributing to Part II. Other significant credits from the 1970s include the role of an Announcer in the series Kamen Rider V3, the character Gamada in Fumō no Kenshi, and Tamashima Daisuke in Yakyūkyō no Uta. His voice work also extended to films such as The Undersea Express and Hana no Kakarichō.

Throughout his career, Sakuma's frequent collaborations included voice actor Norio Wakamoto, with whom he shared credits on several projects. Sakuma's professional activity also encompassed on-screen performance, with an appearance in the 1969 film Until the Bottomless Sea City is Built.