Tsutomu Isobe is a Japanese actor and voice actor born on October 13, 1950, in Tokyo, Japan. He is a graduate of the Toho Gakuen College of Drama and Music. Isobe began his career on stage, joining the Haiyuza Theatre Company in 1972, where he performed in numerous productions, including works by William Shakespeare. He left the company in 1989 to focus on other areas of his career.

Isobe's entry into voice acting was for the film Kramer vs. Kramer. He is highly renowned for his extensive dubbing work, having provided the official Japanese voice for numerous major Hollywood actors for decades, including Harrison Ford, Mel Gibson, Chow Yun-fat, and Sean Bean. This extensive work in dubbing has made his voice very familiar to Japanese audiences.

In the realm of anime and animation, Isobe has portrayed a wide array of characters, often lending his authoritative and distinctive voice to figures of power, mystery, or villainy. Among his notable roles are Heinz in the Magnetic Rose segment of the 1995 anthology film Memories and Vincent Volaju in Cowboy Bebop: The Movie. He has also played roles in adaptations of major franchises, such as George Joestar I in JoJo's Bizarre Adventure: Phantom Blood. In the series Black Lagoon, he voiced the calm and collected leader Dutch. He also played Inspector Lunge in the psychological thriller Monster.

Isobe has been particularly active in original video animations and theatrical films. He has played the role of Dimsdale Boiled across all three films in the Mardock Scramble series. He voiced Gasback in Trigun: Badlands Rumble and Ivan Coral Vega in King of Thorn. In the Mobile Suit Gundam franchise, he voiced Herman Yandel in Mobile Suit Gundam MS IGLOO 2: Gravity Front. He also voiced the character Emmi in the 2013 film Gintama: The Movie: The Final Chapter: Be Forever Yorozuya.

In the 2010s and beyond, Isobe has continued to take on prominent roles in high-profile animated projects. He was the voice of King Regis Lucis Caelum CXIII in both the film Kingsglaive: Final Fantasy XV and its companion anime series Brotherhood: Final Fantasy XV. He voiced Guillermo Garcia in the 2019 film Psycho-Pass: Sinners of the System. That same year, he played the powerful Douglas Bullet in the popular One Piece film Stampede. In 2022, he voiced Emperor Hadrian in the Netflix original anime Thermae Romae Novae. He has also appeared in the Star Wars: Visions series in the role of Mitaka.

Beyond anime, Isobe has a significant presence in video games, including high-profile titles such as Final Fantasy XV, Nioh 2, and as the voice of the antagonist Khotun Khan in Ghost of Tsushima. He is also known to tokusatsu fans for his live-action role as Isamu Ozu and the voice of Wolzard in the 2005 Super Sentai series Mahou Sentai Magiranger.

Throughout his career, Tsutomu Isobe has established himself as a highly respected and versatile figure in the Japanese entertainment industry. His deep, resonant voice and experience across stage, live-action television, and voice acting have made him a sought-after talent for a diverse range of roles, from iconic Hollywood dubs to memorable characters in anime and animation. Known for his professionalism and humility, he is considered a veteran and an influence on younger generations of voice actors.