Hideki Nakanishi is a Japanese voice actor born on April 10, 1982, in Akita Prefecture, Japan. He began his career in the voice acting industry in 2005 or 2006 and is affiliated with the talent agency Dandelion. Nakanishi stands approximately 172 to 173 centimeters tall and has B-type blood. He is a graduate of the 81 Produce附属俳优养成所 (81 Produce Affiliated Actor Training School). Early in his career, he was associated with 81 Produce before becoming a freelancer and subsequently joining Dandelion in November 2012.

Nakanishi has built a career through numerous supporting roles in television anime, original video animations, and theatrical films. Among his most recognized performances is the character Hayato Kobayashi within the Gundam franchise, a role he has voiced across multiple projects. This includes the Mobile Suit Gundam: The Origin series, the 2022 theatrical film Mobile Suit Gundam: Cucuruz Doan's Island, and the video game SD Gundam Battle Alliance. Another notable role is Yūnosuke Sakurai in the 2011 anime series Moshidora. His extensive list of anime credits includes appearances in long-running and popular series such as Pokémon, Toradora!, Fullmetal Alchemist: Brotherhood, A Certain Scientific Railgun, and The Seven Deadly Sins. He also voiced a role in the original net animation Kuromukuro.

Beyond animation, Nakanishi has contributed his voice to the video game industry, with roles in franchises like Super Robot Wars and The Prince of Tennis. Throughout his career, he has frequently collaborated with a consistent group of fellow voice actors. Notably, he has worked alongside Mitsu Iwakura in seven productions, Kōsuke Toriumi in six, and Kana Ueda, Tsuyoshi Takahashi, and Satoshi Tsuruoka in five each. His voice is characterized as a tenor, which allows him to portray energetic and versatile characters.