Mauricio started out as a crime reporter at a newspaper, but he quit that job to become a comic book creator. He created Turma da Mônica, which was later translated into Monica's Gang. He drew the children from life, looking at his own children, he has ten, and thinking back on the children he knew when he himself was growing up.
The simple features of his characters made for easy adaptation into all kinds of merchandise. The gang is also featured on a myriad of products.