José Antonio Muñoz studied at the Pan-American School of Art, where he attended classes by Hugo Pratt and Alberto Breccia. He became the assistant of Francisco Solano Lòpez and cooperated with Hector Germàn Oesterheld at age 18. He published in magazines such as Hora Cero and Frontera Extra. He drew several episodes of Hugo Pratt's 'Ernie Pike' series and he illustrated 'Precinto 56' from scripts by Ray Collins in the magazine Misterix. He also cooperated with the British Almagamated Press, through the studios of Solano Lopez. He left Argentina in the early 1970s.
He settled in Europe, and began a collaboration with the scenario writer Carlos Sampayo in Spain. In 1975, they began the series 'Alack Sinner', that appeared in the Italian magazine Linus and in the French magazine Charlie Mensuel. Three years later, they launched 'Sophie Goin' South' in B.D. Starting in 1979, he drew for the magazine À Suivre, where he continued 'Alack Sinner' and created 'Le Bar à Joe' ('Joe's Bar'), 'Histoires Amicales du Bar à Joe', 'Sudor Sudaca', 'Billie Holiday' and 'Trains sur l'Eau', among others. Most of these stories were collected in albums by Futuropolis and Casterman.
Continuing to work for the French market, he drew 'Jeu de Lumières' for publisher Albin Michel in 1988. Two years later, he was present in L'Écho des Savanes with 'Europe en Flammes'. In the following years, Munoz participated in the collective album 'Au Secours!' for Amnesy International, and contributed stories like 'La Magolfa' (with scriptwriter Farnetti) in À Suivre. Muñoz collaborated with the renowned US crime writer Jerome Charyn on the books 'Le Croc au Serpent' (À Suivre, 1996) and 'Panna Maria' (Casterman, 1999).
José Muñoz illustrated 'Les Damnés de la Pampa' by his compatriot Manuel Prado in 1997, and he published the albums 'Automne en Printemps' and 'Le Poète', collections of his stories for À Suivre with Sampayo, with the publishing house Amok in 1998. His illustrated stories 'Orillas de Buenos Aires' and 'Carnet Argentin' were published by Beaulet in 1999 and 2000.
For the Italian publisher Hazard, he made 'Hombre di China' in 2001. He continued his collaboration with Sampayo on the short story collection 'Dans les Bars' (Casterman, 2002). For the same label, he worked with Daniel Picouly on 'Retour de Flammes' in 2003. In 2007 he won the Grand Prix of the festival of Angoulême.