His work is defined by a mastery of light and shadow inherited from his teacher, Sebastiano Ricci. Fontebasso often used high contrast to give his figures a sculptural presence. In works like The Virgin and Child Presenting the Rosary to Saint Dominic and Saint Catherine of Siena, he avoided the airy lightness of some Rococo contemporaries. Instead, he preferred solid forms and clear compositions. His drawings, such as Two Male Nudes, show a technical precision that grounded his larger painted scenes.

Modern collectors value Fontebasso for his ability to balance theatrical drama with intimate detail. His prints and paintings do not rely on excessive ornamentation. They offer a sense of narrative clarity that fits well in contemporary spaces. The earthy tones and strong figurative elements in pieces like Hagar in the Desert provide a sophisticated aesthetic. His art represents a bridge between the grand Baroque tradition and a more direct, human-centred style.