Roberto Castro was born in the city of Lima, and studied painting and drawing at the Escuela Adelina Concha de Dibujo and at the Escuela Nacional De Bellas Artes. Among his first jobs was illustrating the novel 'Matalache' by the Peruvian author López Albujar, but due to the political climate in the country, he couldn't finish his work.
Castro then went to work for the political magazine, X, where he illustrated articles on political subjects. Afterwards, he returned to continue his studies in fine arts. Castro also took on humorous illustrating for the Gente review. In 1980, he headed for Mexico, and went to work for newspapers and the magazine Novelas Inmortales, where he illustrated comic adaptations of novels. He has worked on comics for the publisher Ejea, including contributions to the magazine Artes Marciales. For the American market, he has worked on titles like 'Star Trek' (DC) and 'Conan' (Marvel).