Mario Casartelli began his career as a cartoonist in the Paraguayan press in 1977. His drawings first appeared in the newspaper La Tribuna and later in Hoy. In 1978, he joined Ultima Hora, one of Paraguay's three main newspapers, for a two-year stint. In 1989, he returned to the paper, where he has since published a daily editorial cartoon and a weekly satirical poetry column. On occasion he contributes articles on literature as well as on Paraguayan and global politics. He has written several poetry books and has received numerous literary awards. He is also a singer-songwriter and an active member of the José Marti Paraguayan-Cuban Cultural Association. His latest book, Palestine: the key between the rocks, was published in 2011.