After attending the School of Fine Arts in Paris, Robert Lortac began his career in 1900 as an illustrator for magazines like Le Bon Vivant, Polichinelle, L'Illustré National, Le Pêle-Mêle, Le Matin and Le Bonnet Rouge. During World War I, he began working with Emile Cohl on animation projects. He travelled through the US with an exposition of work by mobilized French authors and he had his own animation studios in Montrouge from 1919 to 1944. In addition, he began writing crime and science fiction novels in the 1930s.
Lortac's first comics were 'Démonax', published in Gavroche in 1941, and 'A la Découverte de Ker Is' in O Lo Lè in 1942. In the following years, he focused on comic scriptwriting instead of drawing. He wrote 'Les Pieds Nickelés' for René Pellos in L'Épatant from 1948, and 'Tétar-Zan' for Mat. Most of his scripts were for the collections of publisher Artima. For the Giordan brothers, he scripted series like 'Vigor' and 'Tom Tempest', as well as stories for Météor. He also created 'Tim et Tom' with Jean-Paul Decoudun and worked on 'Mademoiselle Swing' with Jean-Claude Forest in La Semaine de Suzette.