Kenjirō Ishimaru is a Japanese actor, voice actor, and narrator born on November 1, 1953 in Oita Prefecture, Japan. He began his career in the entertainment industry in 1977, making his debut in a stage production of Itsudemo Kokoro ni Taiyō o. After leaving Nihon University's College of Art, where he studied theatre, he was scouted and joined the agency of the playwright Mineo Kanehara. As of January 1, 2006, his career has been managed by the agency Seinenza Eiga Hōsō.

Ishimaru is most widely recognized for his decades-long role as the narrator of the long-running Japanese travel show See the World by Train, a position he has held since the program began broadcasting in June 1987. His calm and steady vocal delivery has made him a familiar presence in Japanese television, particularly for programs related to railway travel. Ishimaru has also frequently appeared as a traveler on another long-standing railroad-themed show, Burari Chūsha no Tabi.

In the realm of animated works, Ishimaru has provided his voice to multiple series. He serves as the narrator for the anime adaptation of the popular manga Toriko, a continuation of the role's prominence in his career. More recently, he voiced the character Teruchika Yodogawa in the 2024 series Golden Kamuy -The Hunt of Prisoners in Hokkaido-.

While his voice work is extensive, Ishimaru is also a prolific on-screen actor. One of his most beloved live-action roles is the enigmatic Owner (also known as the Station Master) of the time-traveling DenLiner train in the tokusatsu superhero franchise Kamen Rider Den-O. He has reprised this role in numerous subsequent films within the Kamen Rider franchise, including OOO, Den-O, All Riders: Let's Go Kamen Riders. His other notable television appearances include the long-running detective series Inspector Totsukawa, where he plays the character Detective Kamei.

Ishimaru has an extensive filmography that spans several decades, often appearing in major film productions. His film credits include a role in the 1989 drama Black Rain, directed by Shōhei Imamura. In the horror genre, he played Detective Omuta in Ring 2 (1999). In 2001, he appeared as the Head of Onmyoji in the supernatural period film Onmyoji. He also took on the role of the Vice Principal and Gosenemon in several films within the Kekko Kamen series, including Kekko Kamen, Kekko Kamen Returns, Kekko Kamen: The MGF Strikes Back, and Kekko Kamen Surprise!. In 2017, he appeared in the live-action film adaptation of Fullmetal Alchemist, playing the character Cornello. His other film work includes roles in Lost Paradise (1997), Always Sanchōme no Yūhi (2005), and Baian the Assassin, M.D. (2023).

In addition to his professional work, Ishimaru is known for his athleticism and adventurous spirit. He has been a regular competitor on the sports entertainment television programs Sasuke (known internationally as Ninja Warrior) and Sportsman No. 1. His hobbies include rock climbing, windsurfing, mountaineering, and dancing, with tap dancing listed as one of his specialties as well.