Takehito Koyasu is a highly accomplished and prolific Japanese voice actor, born on May 5, 1967, in Yokohama, Kanagawa Prefecture. He is affiliated with and serves as the representative of T's Factory, a voice acting agency he founded in October 1998. His son, Koki Koyasu, has also followed in his footsteps to become a voice actor. In recognition of his talent and contributions to the industry, Koyasu won the Best Actor in Supporting Role award at the 15th Seiyu Awards in 2021.

Koyasu's path to voice acting began in his junior high school years. An avid movie fan, he was inspired to pursue a career in acting after being moved by a scene in the film Adieu Galaxy Express 999. This experience sparked his interest in what he terms "three-dimensional acting," a principle that has guided his career. After high school, he enrolled in a training school and made his professional voice acting debut in 1988 with the anime Wowser. His first regular role came in 1989 as Gai, the King Yaksha, in Legend of Heavenly Sphere Shurato, a role that, while raising his profile, proved challenging due to its complexity as a villain with little internal monologue. An early setback occurred with the OVA Aries in 1990, where despite winning a fan vote to voice the lead character, the production team deemed him too inexperienced and instead cast him in a minor role. A pivotal moment in his early career was his portrayal of the main character's rival, Tekkaman Evil (Shinya Aiba), in Tekkaman Blade. Koyasu has often cited this as his favorite character, a role he pursued with great personal investment and which he credits with revitalizing his voice acting career.

Throughout his extensive career, Koyasu has become known for his deep, smooth voice, frequently lending it to charismatic villains and bishōnen characters, though he has also demonstrated great versatility in comedic and lively roles. Some of his most iconic and internationally recognized roles include Dio Brando in the JoJo's Bizarre Adventure series, Zeke Jaeger (the Beast Titan) in Attack on Titan, and Shinsuke Takasugi in Gintama. His filmography is vast and spans decades, featuring a wide array of characters such as Ryosuke Takahashi in Initial D, Kururu in Sgt. Frog, Excalibur in Soul Eater, Admiral Aokiji/Kuzan in One Piece, Mu La Flaga in Mobile Suit Gundam SEED, Roswaal L. Mathers in Re:Zero - Starting Life in Another World, and the titular hero in Bobobo-bo Bo-bobo. Beyond anime, he has voiced numerous characters in video games, including Sett in the Japanese version of League of Legends, Lon'qu and Seteth in the Fire Emblem series, and Harvey in Octopath Traveler II.

In addition to his voice acting, Koyasu has been involved in creative and musical projects. In the late 1990s, he contributed to the conceptualization of the media franchise Weiß Kreuz. He also formed the voice acting unit Weiß with his co-stars Shinichiro Miki, Tomokazu Seki, and Hiro Yuki, becoming the first male voice actor to appear on the cover of a voice acting magazine and to create a music video. He was also active as a musician under the name ZAZEL in 2000 and 2001.

Koyasu has a history of collaboration with several fellow voice actors, most notably the members of the Weiß unit. He has also taken over many of the voice roles originally performed by Kaneto Shiozawa following Shiozawa's death. His work is characterized by a wide-ranging versatility, moving effortlessly from the flamboyant villainy of Dio to the comedic absurdity of Bo-bobo. In 2020, he appeared alongside his son, Koki Koyasu, in an advertisement for Duel Masters, and the two also co-hosted a radio show together. His personal motto is "to make two-dimensional into three-dimensional," reflecting his lifelong passion for bringing animated characters to life.