Kōki Ohsuzu is a Japanese voice actor from Tokyo, born on October 5. He is affiliated with the talent agency Vims and is a graduate of the Japan Narration Acting Institute. His hobbies include rakugo and games, and he is skilled in basketball.

Ohsuzu's first major leading role came in 2022 when he was cast as the protagonist Ashito Aoi in the television anime Aoashi. This performance as the ambitious young soccer player is considered one of his most significant and career-defining roles to date. In the same year, he also voiced the character Kanna Shimodaira in the Animation x Paralympic project.

Since his debut, Ohsuzu has built a diverse portfolio of supporting roles in a wide array of popular anime series. His notable credits include Draht in Frieren: Beyond Journey's End, Hyoga in Edens Zero, and a student council member in 2.5 Dimensional Seduction. He has also appeared in major productions such as Dan Da Dan, Fairy Tail: 100 Years Quest, and Blue Box. In the series Tasuketsu -Fate of the Majority-, he voiced the recurring character Kazuhiko Sato.

In the children's educational anime series Gakkō dewa Oshiete Kurenai Taisetsu na Koto, which began airing in 2025, Ohsuzu voices the character Kattan, also known as Tama, a cat and gaming buddy to one of the main characters.

Beyond anime, Ohsuzu's work encompasses a range of voice acting fields. He has contributed to video games, with roles such as the protagonist in Dragon Quest VII Reimagined and Aoshi in Monster Strike. He is also active in audio dramas, dubbing foreign dramas like Ghost Girls, and has participated in numerous live events and stage readings, including a performance in The Little Prince.