Family from the village of Rezzonico, now the municipality of San Siro, in the province of Como and located on the lake of the same name. The genealogical branch separated around 1550 from the noble Della Torre di Rezzonico.
The two brothers Carlo and Aurelio, who conducted "the business of the royal mines of Adriano", were appointed by Emperor Leopold I, Barons of the Holy Roman Empire as a reward for the good deals concluded in his name. From Lake Como they moved respectively to Genoa and Venice.
Aurelio Rezzonico arrived in Venice around 1640, where he expanded the trade of his brotherly activity, accumulated a great fortune in a short time, maintaining a relationship of trust with the Genoese merchant class. He showed great generosity by donating 60,000 scudi to the San Lazzaro dei Mendicanti Hospital, one of the most important relief organizations of the time. In the church, currently incorporated in the perimeter of the Civil Hospital, he built the family tomb where he was buried in 1682.
Quintiliano Rezzonico, who lived in the Palazzo Fontana in Cannaregio, succeeded his uncle's death in taking care of the flourishing family business, and distinguished himself for having offered, on April 8, 1687, also in the name of the brothers Abbondio and Giovanni Battista, the substantial sum of 100,000 ducats (60 as a gift and 40 on loan) to the Serenissima in economic support of the continuous wars of those years against the Turks. Following this huge offer, the Venetian Senate ascribed the Rezzonico family to the register of nobility. His brother Giovanni Battista, podestà of Treviso, married Vittoria Barbarigo in 1690 with whom he had two children, Aurelio who became Procurator of San Marco, and Carlo who was the most famous character of the Rezzonico family as he became first bishop of Padua, then Pope Clement XIII. He was baptized on 29 March 1693 in the parish church of San Felice, as can still be read on the plaque placed at the entrance to the sacristy.
With the death of Abbondio Rezzonico in 1810, the powerful family died out, and his sister Quintilia, married to the noble Lodovico Widmann, inherited the Venetian Rezzonico heritage.