Tomokazu Seki is a veteran Japanese voice actor and singer born on September 8, 1972, in Tokyo, Japan. He is affiliated with the talent agency Atomic Monkey, where he also holds the position of honorary president. Beyond his voice work, he is the chairman of the theater company HeroHero Q.

Seki's career began in 1993 with his first role in the anime Mobile Suit Victory Gundam. He quickly rose to prominence, becoming known for his energetic and hot-blooded performances in a wide variety of leading roles throughout the 1990s and 2000s. His filmography is extensive and includes many iconic characters across multiple genres. He is well known for his long-running role as Suneo Honekawa in the Doraemon anime series, a part he has played since 2005. In the Pokémon anime, he voiced Tracey Sketchit, a companion of Ash Ketchum during the Orange Islands arc. He also voices Whisper in the Yo-kai Watch franchise, a role that brought him significant mainstream popularity.

Seki is equally celebrated for his work in series aimed at older audiences. He has played a multitude of memorable characters such as the arrogant Gilgamesh in the Fate series, the determined Shinya Kogami in Psycho-Pass, the eccentric Itaru Hashida in Steins;Gate, and the passionate Sousuke Sagara in Full Metal Panic!. In the mecha genre, he is renowned for his roles as Domon Kasshu in Mobile Fighter G Gundam and Yzak Joule in Mobile Suit Gundam SEED. His range extends to villains and complex characters, as demonstrated by his performances as Enrico Pucci in JoJo's Bizarre Adventure: Stone Ocean and Sanemi Shinazugawa in Demon Slayer: Kimetsu no Yaiba.

Throughout his career, Seki has frequently collaborated with a network of fellow prominent voice actors, including Takehito Koyasu, Hideo Ishikawa, and Shin-ichiro Miki, with whom he formed the popular voice actor unit Weiß Kreuz. His talent and enduring popularity have been widely recognized; in a 2017 Asahi TV poll, he was ranked the fifth most popular voice actor in Japan.

In addition to his anime roles, Seki is an avid fan of tokusatsu (special effects) productions and has made numerous appearances in live-action series and films, often voicing equipment or playing minor roles in franchises like Super Sentai and Ultraman. His passion for theatre is also a significant part of his career, as he writes, directs, and acts for his own theater company, HeroHero Q. This combination of mainstream success, genre-defining performances, and dedication to the craft of acting has cemented Tomokazu Seki's status as one of Japan's most respected and versatile voice actors.