Sanji Hase was a Japanese voice actor born Hirō Hase on January 2, 1936, in Tokyo. He was active in the industry from 1963 until his death on March 8, 2002, from lung cancer at the age of 66. Throughout his career, he was affiliated with the talent agency Aoni Production before becoming a free agent in his later years. He was the father of fellow voice actor Arihiro Hase.

Hase's career spanned several decades and included a wide variety of roles in anime, dubbing, and narration. He is perhaps best known for his role as Kazuo Nakano, often referred to as Aderans Nakano-san, in the long-running series Kinnikuman, a character that is considered one of his most iconic. His filmography demonstrates his versatility, with significant roles in numerous classic anime series from the 1960s through the 1990s. He voiced Shūnen in the series Ikkyū-san and its related specials. In the Toei Animation magical girl series Hana no Ko Lunlun, he provided the voice for the character Yabōki. He was also the first voice actor for Mr. Honekawa in the beloved franchise Doraemon.

Hase was a regular presence in the works of manga artist Shigeru Mizuki, contributing voices to multiple iterations of the GeGeGe no Kitaro franchise. In the 1971 series, he was the first voice for the character Konaki Jijii, and in the 1985 series, he voiced numerous characters including Hakusanbō, Hiderigami, and others. Another of his notable and long-running roles was as Chang Changku, the cyborg 006, in the 1979 version of Cyborg 009. He also played Tensai Tsuji in Magne Robo Gakeen and Chō-san in Majokko Megu-chan. Among his other numerous anime credits are roles in Devilman, Yatterman, Cutey Honey, High School! Kimengumi, Akazukin Chacha, and the 1990 version of Mōretsu Atarō.

In addition to his work in anime, Sanji Hase was active in dubbing foreign films and series. His dubbing credits include providing the Japanese voice for Gideon the cat in the Disney film Pinocchio, Joe in Lady and the Tramp, and Fflewddur Fflam in The Black Cauldron. He is also noted for his narration work, including for the series Monchichi, the Twins. His contributions to the industry left a mark on Japanese animation during its formative and golden ages.