Guillermo studied about makeup for special effects at Dick Smith's Advanced Makeup Course.
In 2007 Guillermo was nominated for Oscar for Best Original Screenplay and Best Foreign Language Film for his movie Pan's Labyrinth. Because of this nominations he also became one of the 10 Mexican Oscar-nominees.
In 2007 Guillermo and his friends Alfonso Cuarón and Alejandro Gonzalez Inarritu, created the independent production company.
Instead of filming Blade Trinity, Alien vs. Predator and Harry Potter and the Prisoner of Azkaban, Guillermo preferred to make his dream project Hellboy.
Guillermo was educated at University of Guadalajara, in Mexico.
Guillermo frequently films the insects in his movies.
His favorite film director is John Carpenter.
In an radio interview in 2007 he told Terry Gross of "Fresh Air with Terry Gross" that his grandmother would require him to mortify himself in self-punishment, in one case placing metal bottle caps into his shoes so that the soles of his feet were bloodied while walking to school. She also tried to exorcise him on two occasions because he continued to draw monsters from his imagination.
His favorite movies are Frankenstein's Monster and Creature from the Black Lagoon.
Guillermo was so dedicated to shooting the film Hellboy II: The Golden Army that he passed on directing I Am Legend (2007) Harry Potter and the Half-Blooded Prince (2008) and Halo (2009).
In December of 2007 he was ranked #37 on "Entertainment Weekly's" The 50 smartest people in Hollywood .
Because of various religious beliefs, Guillermo turned down the chance to direct the film Hellraiser: Bloodline (1996)
In 2006, due to extreme heat conditions of shooting the film Laberinto del fauno, El (Pan's Labyrinth) on location in Spain, Guillermo lost upwards of 45lbs.
In 1997 his father was kidnapped in Mexico for 3 months and later released when his ransom was paid.
Guillermo was born with a photographic memory.
In a four year span after seeing The Texas Chainsaw Massacre (1974), Guillermo became a vegetarian. He is no longer a vegetarian but continues not to eat red meat or pork.
Born into a devout Catholic home, Guillermo displays that faith by including various religious toned themes and artifacts in his films.
Guillermo is 5'10" (178cm).
Guillermo: (2002, On actor Ron Perlman). Aside from being a perfect 'Hellboy', he is a gentleman, a friend to die for, a great actor and - for the ladies - he has the sexiest male voice this side of Barry White. What more can one ask for?
Guillermo: I was an altar boy, a spokesperson for the Virgin Mary, I was a choir boy but then at the age of 14 I discovered self gratification and all that went out the window.
Guillermo: I like actors that are good with pantomime and that can transmit a lot by their presence and attitude more than through their dialogue.
Guillermo: Pan's Labyrinth is a fairy tale, but it's not mamby-pamby and goody-goody. Fairy tales have nastier endings than pretty much any category of literature. That's why I love them! This is a fairy tale, but it is not a movie for children by any stretch.
Guillermo: Weird, like beauty, is in the eye of the beholder, so weird is acceptable to me.
Guillermo: Guilt is part of being Catholic and I think that once a Catholic, always a Catholic. You're screwed, you know. I feel guilty 23 hours a day. I feel guilty even when I'm sleeping.
Guillermo: I really don't care much about the idea of normal - that's very abstract to me. I think that perfection is practically unattainable but imperfection is right at hand.
Guillermo: I have said sometimes that I have spent 32 years recuperating from my first 10 years. Really. I had a pretty screwed up childhood, living in Mexico.
Guillermo: The sign of a true friendship is when you can forgive success.
Guillermo: When you have the intuition that there is something which is there, but out of reach of your physical world, art and religion are the only means to get to it.
Guillermo: (on "Pan's Labyrinth") I'm not proselytising anything about a lion resurrecting. I'm not trying to sell you a point. I'm just doing a little parable about disobedience and choice. This is my version of that universe, not only Narnia, but that universe of children's literature.