Guillermo Romero is a Spanish voice actor born on August 3, 1967, in Talavera de la Reina, Toledo, Spain. His career in media began in the late 1980s as a radio broadcaster on Radio 80, followed by a position as a promotional announcer for the Antena 3 television network, where he became the voice for programs such as La Ruleta de la Fortuna and El Precio Justo. He transitioned into voice acting in 1990, with his first lead role being the Spanish dubbing voice for Johnny Depp in the film Ed Wood.

Romero has become a prominent figure in the Spanish dubbing industry, providing voices for a vast array of characters in film, television, and animation. He is particularly well-known for being the regular Spanish dubbing voice for several international actors, including Edward Norton, Noah Wyle, Eric Dane, Oscar Isaac, Jason Sudeikis, Chris Pratt, and Henry Cavill. His extensive body of work includes voicing iconic characters such as Superman in multiple films, Peter Quill / Star-Lord in the Marvel Cinematic Universe, and Poe Dameron in the Star Wars sequel trilogy. In animation, he has lent his voice to Lightning McQueen in the Cars franchise, Remy in Ratatouille, and Mario in The Super Mario Bros. Movie.

In the realm of anime and animated series for a general audience, Romero has taken on notable roles. He voices the character Keith Goodman, also known as the superhero Sky High, in both the Tiger & Bunny television series and its sequel, Tiger & Bunny 2. He also provides the voice for the protagonist Ethan in the Spanish dub of the anime series Dragon's Dogma. Beyond these, his dubbing credits include the role of David Rourke in the film The Ring Two and Ozzy in the animated film Ozzy. Romero remains an active professional in the field of dubbing and voice acting.