Keiju Kobayashi was a celebrated Japanese actor whose career in film and television spanned over six decades. Though primarily known for his extensive work in live-action cinema, he also contributed his voice to a small number of notable anime productions.

Born in Gunma Prefecture on November 23, 1923, Kobayashi began his acting career in 1942 after leaving Nihon University to join the Nikkatsu studio. He later moved to the Toho film company in 1956, where he became a defining figure in popular post-war cinema. He was particularly famous for his roles in the long-running Company President comedy film series, where he helped shape the popular image of the Japanese salaryman. Over his career, he appeared in more than 250 films, working with acclaimed directors such as Akira Kurosawa, Yasujirō Ozu, and Mikio Naruse. His talent was recognized with multiple best actor awards from the Mainichi Film Awards for his performances in films like The Naked General (1958) and The Elegant Life of Mr Everyman (1963). In the late 1960s, he successfully transitioned to television, continuing to deliver powerful performances.

While his primary legacy is in live-action, Kobayashi's distinctive presence extended to anime through a handful of voice roles. In the 1995 Studio Ghibli film Whisper of the Heart, he voiced Shirou Nishi, the kindly antique shop owner who serves as a mentor to the protagonist and the grandfather of the male lead. He also lent his voice to historical and dramatic anime projects. He provided the narration for the 2005 anime film Nagasaki 1945: The Angelus Bells, which depicts the atomic bombing of Nagasaki. Additionally, he voiced the role of Shinran Shonin in the original anime video Nenbutsu Monogatari: Shinran-sama - Negai, Soshite Hikari.

Keiju Kobayashi passed away on September 16, 2010, at the age of 86. His career is remembered for its remarkable longevity and the profound impact he had on Japanese cinema, with his few voice roles in anime serving as a unique part of his vast and celebrated body of work.