Atsushi Imaruoka was born on May 23, 1972, in Isesaki, Gunma Prefecture.
Before becoming a voice actor, Imaruoka was a professional boxer belonging to the Kyoei Boxing Gym, having been devoting himself to amateur boxing since high school. Imaruoka also moved to Tokyo in the hopes of becoming an actor. In order to become an actor, Imaruoka decided to exercise seriously, which led him to acquiring a boxing license and made his professional debut as a boxer at the age of 24.
In 2001, Imaruoka joined the acting training center attached to Mausu Promotion and has been affiliated with the agency since then. He learned alongside Miyuki Sawashiro.