Born in São Paulo, Ignácio Justo published his first comic, 'Aventuras de Paulinho', in Adolfo Aizen's Suplemento Juvenil when he was only 10 years old. He was in the Brazilian military in the early 1950s, took on aviating, but eventually chose an artistic profession. He began to draw professionally in 1959, when he joined the publishing house Continental. There, he illustrated war and terror comics. Throughout his career, he has mainly done war and aviation stories, among others for Edrel, Abril and Pan Juvenil.
His stories about the Brazilian Navy and Army appeared in Abril's Almanaque Disney and his jokes and cartoons appeared in the Edrel magazines. He joined Editorial Taiko, the successor of Contintental, in 1971 and was one of the main contributors to M & C Editores (Minami e Cunha). Through his studio, he helped launch the careers of among others Pedro Mauro Moreno, Natanael Fuentes, José Luiz Pinto, Egberto Barbosa, Lincoln Ishida, Aparecido Cocolete, Wanderley Felipe, Antônio Fernandes Filho (Tony Fernandes), Agenor Silva, Ingo Passolde, Alcione Arauda and Marcos Silva.