Mario Castañeda is a Mexican voice actor and dubbing director, born on June 29, 1962, in Irapuato, Guanajuato, Mexico. He began his career in voice acting in June 1983 after studying dramatic acting at the Andrés Soler Institute in Mexico City from 1979 to 1982. With a career spanning over four decades, he is widely recognized for his work in Japanese anime, particularly as the iconic Latin American Spanish voice of the adult Son Goku in the Dragon Ball franchise.

In the realm of anime, Castañeda's most prominent role is Son Goku, which he has voiced across numerous series and films including Dragon Ball Z, Dragon Ball GT, Dragon Ball Super, and the theatrical films Dragon Ball Super: Broly and Dragon Ball Super: Super Hero. He initially hesitated to take on the role of Goku, concerned that fans might not accept a change in voice for the character, but was persuaded by his son, Arturo Castañeda, who would later also become a voice actor in the franchise. His involvement with the series extends beyond the main character, as he has also voiced related characters such as Bardock, Turles, and Goku Black in various Dragon Ball media. His other significant anime voice roles include Kanon in Saint Seiya, Hidan in Naruto Shippuden, Neflyte in Sailor Moon, and Akainu/Sakazuki in One Piece. He has also contributed to other animated projects, such as voicing Zapp Brannigan in the Latin American dub of Futurama.

Beyond anime, Castañeda has had an extensive career dubbing live-action films and series. He is the recurring Spanish voice for several Hollywood actors, most notably Jim Carrey, Bruce Willis, and Mark Ruffalo. His dubbing work for Jim Carrey includes performances in films like Ace Ventura, Liar Liar, The Grinch, and the Sonic the Hedgehog film series. For Bruce Willis, he has provided his voice in movies such as The Fifth Element, Armageddon, and the Look Who's Talking films. As Mark Ruffalo's regular Spanish dubbing voice, he portrays Bruce Banner / Hulk in the Marvel Cinematic Universe films. His live-action dubbing work also includes narrating the adult Kevin Arnold in The Wonder Years and voicing the title character in MacGyver.

Castañeda has also worked extensively as a dubbing director. He served as the director for the animated series El Chavo animado, in which he also voiced the characters Don Ramón and Ñoño. He was the official announcer for the Boomerang television channel in Latin America from 2001 to 2006. Throughout his career, he has held positions such as creative director at SDI Media de México and has lent his voice to characters in video games, including League of Legends, Smite, and World of Warcraft.

His contributions to the entertainment industry have been recognized with a star on the Plaza de las Estrellas in Mexico, where he was the first voice actor to be honored with a bronze imprint of his hands in January 2019. He is also the author of the book Elegido por el doblaje, published in 2020. Castañeda is frequently invited as a guest to conventions and events across Latin America and the United States, such as Otakon, to speak about his work and career in dubbing.