Rafael López Espi began his career in 1953, drawing war stories for the publishing house Simbolo. His work also appeared in the press, varying from comics ('La Atlántida', 'Los Tambores del Bruc' in Solidaridad Nacional) to illustrations (in La Prensa). Soon afterwards, he went to work for Josep Toutain's agency, where he started out doing comics for the color supplement of La Prensa. Later on, he drew romance comics for the British magazine Glamour, followed by western strips. During the 1960s, his foreign work increased, when he started drawing for Bardon Art and Luis Ferraz, with whom he made the series 'Don Starr'. López Espi illustrated western titles like 'Rex Raven', 'Billy McGregor' and 'Riffle', as well as several war and romance stories for the British Fleetway (Roxy, Marilyn, Valentine).
López Espi left Toutain's Selecciones Illustradas in the mid-1960s. He focused on illustration work, but continued to do comics for the Spanish publisher Toray, such as the western stories in the collection Historias del Oeste. In 1969, he joined the publishing house Vértice, where he did cover illustrations (among others for '3-09 Agente Secreto'), as well as the comic series 'Mytek'. He left the comics scene for several years, until in 1992, he began a collaboration with the Swedish agency Dalger Press.