From a prosperous family, Villoresi could afford to buy a car and began competing in local rallies at the age of twenty-two with a Lancia Lambda and a few years later acquired a Fiat Balilla with which he and his brother Emilio competed in the Mille Miglia.
Chiron je zmagal še na dirki za Veliko nagrado Casablance in dirki Grand Prix de la Marne.