Caio Guarnieri is a Brazilian voice actor known for his work in the dubbing of numerous anime series and films for the Brazilian Portuguese market. Born in São Paulo on January 20, 1991, he comes from a family with a strong legacy in voice acting, being the son of the renowned dublador Tatá Guarnieri and the brother of fellow voice actress Isabella Guarnieri. This familial connection has seen him collaborate with his relatives on various projects, such as in the anime The Genius Prince's Guide to Raising a Nation Out of Debt, where he voiced the lead role of Wein Salema Arbalest while his sister Isabella voiced the character Ninym Ralei and his father Tatá Guarnieri voiced Hagar.

Guarnieri has built a diverse and extensive portfolio, lending his voice to a wide range of characters in popular anime. He is recognized for his performances in major titles, including the role of Kinro in Dr. Stone and Dr. Stone: Stone Wars, Mirio Togata in My Hero Academia, and Yota Murakami in Gleipnir. His repertoire also includes leading roles such as Wein Salema Arbalest in The Genius Prince's Guide to Raising a Nation Out of Debt and Keisaku Asano in the Netflix series revisions. In the world of feature films, he has contributed his voice to significant projects, portraying Takeshi Goda, also known as Gigante, in both Stand By Me Doraemon and its sequel Stand By Me Doraemon 2.

His work extends beyond these prominent examples to include a variety of other anime and animated series. Guarnieri has voiced characters such as Sabito in Demon Slayer: Kimetsu no Yaiba, Klein in the Sword Art Online franchise, Marlo Freudenberg in Attack on Titan, Kouki Amanogawa in Arifureta: From Commonplace to World's Strongest, and Lean Valhalla in Beyblade Burst Sparking, among many others. His range also encompasses roles in series like ID: INVADED, Bakugan Battle Planet, Yo-kai Watch, and the film The Tale of the Princess Kaguya. In addition to his extensive anime work, he has been part of the Brazilian voice cast for major international productions, providing additional voices for The Super Mario Bros. Movie. Through his consistent and versatile performances across a multitude of beloved series and films, Caio Guarnieri has established himself as a prominent and active figure in Brazilian dubbing.