As a self-taught artist, Cortez made his comic debut in July 1944 in the weekly publication "O Mosquito," under the mentorship of Eduardo Teixeira Coelho.

He later briefly worked as a cartoonist for "O Dia" and commenced his comic book career by creating strips for "Diário da Noite" ("Caça aos tubarões" and "O Guarany").

In this periodical, Cortez crafted comic book stories, cartoons, and honed his color techniques, incorporating Kodak photographic retouching inks, a form of watercolor.

He created covers across genres, achieving great success with magazines like "Terror Negro," "Sobrenatural," and children's titles such as "Contos de Fada," "Varinha Mágica," the duo Oscarito and Grande Otelo, and the comedic Mazzaropi.

From July 17 to 19, 2015, the artist was honored at the 21st Fest Comix (São Paulo) with the exhibition "Grande Mestre dos Quadrinhos: Jayme Cortez," featuring replicas and original works.

In the first Angelo Agostini Award in 1984, Cortez received the title of "master" alongside Eugênio Colonnese, Messias de Mello, and Rodolfo Zalla.