Yukito Nishii is a Japanese actor and voice actor born on June 14, 1995, in Saitama Prefecture, Japan. He began his entertainment career after winning the grand prize in the fifth D-Boys auditions in 2008 at the age of twelve, becoming the youngest winner in the group's history. He became a founding member of the D2 sub-unit in July 2009. His early work was primarily in live-action television dramas and film, with his debut film role being Shūya Watanabe in the 2010 movie Confessions.

Nishii's most prominent and widely recognized voice acting role came in 2012 when he voiced the character Ame in the critically acclaimed animated film Wolf Children. In the film, he provided the voice for the young boy Ame during his adolescent years, the son of a human mother and a werewolf father who must navigate his dual identity. This role marked his debut as a voice actor, or seiyū. The film itself, directed by Mamoru Hosoda, was a major success, winning numerous awards including the Animation of the Year award at the 2013 Japan Academy Prize. Nishii's performance as Ame contributed to a film that achieved a worldwide box office gross of over 43 million dollars.

While Nishii has maintained an extensive career as a live-action actor in film, television, and stage productions, his voice acting credit for Wolf Children remains his most notable and defining work in the field of animation. His other acting credits include roles in films such as Lesson of the Evil and Suzuki-sensei, as well as television dramas like 35-sai no Kōkōsei and Kamen Rider Ex-Aid. In 2021, he departed from the Watanabe Entertainment agency and, after a period as a freelance artist, affiliated with Office NOVAI entertainment in 2023.