His style draws heavily from the Umbrian school, particularly the work of Perugino. Massaro used balanced compositions and clear, architectural backgrounds to frame his subjects. In pieces like The Virgin and Child, he applied a soft treatment of light and shadow to define form. He avoided the heavy ornamentation common in some Roman works of the period. Instead, he preferred a restrained palette and precise draughtsmanship.

Modern collectors value Massaro for the calm and order present in his religious scenes. His paintings offer a window into the transition between the Early and High Renaissance. The clarity of his figures and the structured use of space make his prints suitable for minimalist or traditional interiors. His work represents a specific moment in Italian art where technical precision met a quiet, contemplative atmosphere.