At the age of 16, he began working as an unpaid apprentice at the comics studios of Ricardo and Enrique Villagran in Buenos Aires, where his father had requested that they take him on.
Zaffino made himself a recognised name in his country, working many years in important Argentine comics, like Nippur de Lagash.
On that trip, Zaffino met comics writer Chuck Dixon, and together they produced Winter World, a three part series for Eclipse.
They continued to collaborate on comics, producing the seminal Punisher graphic novels Kingdom Gone and Assassin's Guild, and a Savage Sword of Conan story titled The Horned God.
Zaffino’s last work in the US was a story written by Dixon for the 1996 Batman Black and White mini series.