Kei Tani was a Japanese comedian, actor, and musician born in Tokyo on February 22, 1932, who also built a notable career as a voice actor before his death on September 11, 2010. He began his professional life as a trombonist, performing in jazz bands as a student at Chuo University before leaving to join the City Slickers in 1953. Tani rose to national fame as a member of the comic jazz band The Crazy Cats, which he joined in 1956 alongside Hajime Hana and Hitoshi Ueki. This group became a massive success on television, particularly through the variety show Shabondama Holiday, and in a popular series of Toho comedies such as the Irresponsible (Musekinin) films. His unique one-word nonsense gags, especially gachon, became nationwide buzzwords. Beyond his comedic persona, Tani successfully took on dramatic acting roles and was a regular in the long-running Tsuribaka Nisshi (Fishing Fool's Diary) film series.

While best known for his live-action work, Kei Tani had several significant roles as a voice actor. For the user, he is most recognizable for providing the voice of Monowasure in the 2007 live-action film adaptation of GeGeGe no Kitaro, a character from the classic horror-comedy manga and anime series. He also voiced the character Rōshi in the 2001 film Red Shadow: Akakage. In the anime feature film Jungle Emperor Leo, which is based on Osamu Tezuka's beloved Jungle Emperor (Kimba the White Lion) series, Tani voiced the character Burazza in 1997. His other voice work includes the role of the character Amitsuru in the 2006 film Atagoal wa Neko no Mori and a part in the 1978 television series adaptation of Monkey, where he voiced Daode Tianzun. His filmography also lists a voice role in an unnamed 2018 project featuring the character Domo-kun, indicating posthumous use of his voice or an archival credit.

Throughout his career, Kei Tani was defined by his long-standing and fruitful collaborations. His membership in The Crazy Cats was the most significant, leading to frequent partnerships with fellow members like Hitoshi Ueki and Hajime Hana across dozens of films and television programs. He also worked extensively with director Yoji Yamada and actors Toshiyuki Nishida and Rentarō Mikuni, appearing in many of their projects. In the Tsuribaka Nisshi series, he consistently played the role of Sasaki, a recurring character in over a dozen films from 1988 until near the end of his life. His great achievement was a seamless ability to move between broad physical comedy and more restrained, dramatic performances, all while maintaining a unique public persona that made him a beloved figure in Japanese entertainment for over five decades.