Guillaume was born in 1983 in Marseille the South of France to a Portuguese father and a French mother.

At an early age, he discovered a passion for fabrics and garments from watching his mother sew during her free time.

At the age of 16 he came across a pile of Vogue and this is where he had a revelation to his call in life, he started to draw his first collections.

In the middle of his commerce studies he abandoned them to join the "Lycée Colbert" of Marseille to learn fashion design, draping and sewing. While enrolled he went up to Paris for an internship at the "Atelier Haute Couture" of Jean Paul Gaultier. This is where he was able to witness for the first time the magic of Haute Couture.

His next encounter in the world of fashion was Stephanie Murray, Head of development at Kenzo who took him under her wing.

In 2003 he moved to Paris to do a two year apprenticeship with the house of Kenzo while attending the draping course of "La Chambre Syndicale de la Couture Parisienne" where he learned the magic to transform a sketch into a dress.

After graduating, three days later he started working at Givenchy Haute Couture with Ricardo Tisci as a freelance draper.

Following the advise of his agent Marie Jo Cerdan, he diversified and enriched his experiences by working with different Parisian fashion houses such as Christian Dior Haute Couture with John Galliano, Balenciaga with Nicolas Ghesquière, Yves Saint Laurent, Hermès, Chloé, Isabel Marant and Maxime Simoens.

During those seven years in Paris, he was able to take the best from Haute Couture, which were the limitless creativity and from the luxury ready to wear were the rigorous technics. With this experience his eye for fashion became sharper and he learned to make this his principal tool.

In 2008, during a trip to California he discovered Los Angeles.

He was amazed by its creative energy and the extraordinary potential that the city offers to the fashion universe.

In July 2010, Guillaume made the permanent move to Los Angeles.