Masahiko Nishimura is a Japanese actor whose primary career is in live-action theatre, film, and television, but he has also contributed his voice to a small number of notable anime productions, particularly those from Studio Ghibli. Born on December 12, 1960, in Toyama, Japan, he studied photography at Toyo University, where he met playwright and director Koki Mitani. In 1983, together with Mitani and other actors, Nishimura co-founded the comedy troupe Tokyo Sunshine Boys, a collaboration that would define the early part of his career and establish his reputation for comedic roles. He gained wider recognition in the 1990s through television dramas, notably in Mitani's series Furuhata Ninzaburo, and won critical acclaim and several awards for his film work, including the Japan Academy Film Prize for Best Supporting Actor.

Nishimura's voice acting work, while not as extensive as his on-screen performances, features prominently in the films of Studio Ghibli. His most widely recognized voice role is Kouroku in Hayao Miyazaki's 1997 epic, Princess Mononoke. He later voiced the character Kurokawa in another Miyazaki film, The Wind Rises, in 2013. He also participated in a smaller Ghibli project, providing the voice for Nonaka-kun in the 2002 short film Ghiblies: Episode 2, a role mentioned in the context of the Ghiblies series. Beyond Ghibli, his anime credits include a role in the 2010 film Theatrical Version: Kaidan Restaurant and voicing Inspector Juzo Megure in the 2015 Detective Conan film, Sunflowers of Inferno.

Nishimura's career is marked by a strong and enduring collaboration with writer and director Koki Mitani, which began with their shared time in the Tokyo Sunshine Boys and continued through numerous successful live-action television dramas and films. His collaborations with Studio Ghibli, while less frequent, have connected him with director Hayao Miyazaki in two major feature films. His achievements outside of voice acting include receiving the Elan d'or Award for Newcomer of the Year in 1997, a Japan Academy Film Prize for Best Supporting Actor for his role in Welcome Back, Mr. McDonald, and a Blue Ribbon Award for the same performance. These accolades highlight his standing as a respected and accomplished figure in the Japanese entertainment industry.