Guillermo Cardoso learned the finer points of the comics profession from Ramón Valdiosera. After making his debut by drawing for the Office of Educational Publishing, he illustrated 'Fantasmones', 'Fiat-Lux', 'Tizón', 'El Agui la Negre', 'La Llanera Vengadora' and Cri-cri. He moved to the United States in 1955, where he went to work for Dell Publishing. He did artwork for 'Little Lulu' the Disney's 'Hiawatha'. In the 1960s and 1970s, he illustrated stories for foreign market Disney publications. He also did the artwork on the 1965 Bambi Christmas special in cooperation with Floyd Gottfredson.