Guillermo Portillo Acosta was a Mexican actor renowned for his extensive work in voice dubbing for Latin American audiences, particularly during the Golden Age of radio and cinema in Mexico. His career began in radio, where he was a singer on the station XEW and performed in radio dramas. In 1944, he was contracted by Metro-Goldwyn-Mayer (MGM) to work as a dubbing actor, a pivotal moment that launched a prolific career giving Spanish voices to numerous Hollywood stars.

In the realm of anime, Portillo Acosta is recognized for his work in two notable features. He provided the voice for the character Shaka-nyorai in the 1960 anime film Alakazam the Great, known in Spanish as Alakazam el grande. He also voiced Commander Kirita in the anime series Captain Harlock, which was known in its Latin American Spanish dub as Capitán Raimar or Capitán Harlock. This role in the late 1970s is believed to have been one of his final projects before his retirement.

Beyond his specific anime credits, Portillo Acosta's career was defined by a vast number of dubbing roles for live-action film and television. He became the established Spanish voice for a wide array of prominent actors, including Charlton Heston, Vincent Price, Stephen Boyd, and Walter Pidgeon. His work spanned classic films such as dubbing Vincent Price in The Tomb of Ligeia and Charlton Heston in The Agony and the Ecstasy. On television, he lent his voice to iconic characters, including John Steed in The Avengers and the title character in The Lone Ranger.

His legacy in Mexican dubbing is marked by a career that spanned from the 1940s until his retirement around 1979. Guillermo Portillo Acosta passed away in 2004.