PROC. GIACOMO CORNARO was one of six sons of the powerful and fabulously wealthy Venetian leader Cav. Proc. Giorgio Cornaro (B-29), brother of Queen Caterina Cornaro (B-31) and founder of the Cornaro della Regina branch of the family. Three of Cav. Proc. Giorgio's sons entered the clergy, two rising to the level of Cardinal and one to Archbishop. Each of the other three sons sired a line of the family that was to sustain the wealth and power of the Cornaro della Regina branch of the family for generations.

Proc. Giacomo was the progenitor of the S. Maurizio line. His brothers Cav. Proc. Giovanni Cornaro (B-63/G-1) and Sen. Girolomo Cornaro (B-64/H-1) were progenitors of the S. Polo and S. Cassiano lines, respectively.

Proc. Giacomo began his career as Podestą [governor] at Chioggia in 1515 and was elected to the Senate in the same year. In 1526 he was elected to the Council of Ten but was later held to have abused his authority in that post and was barred from public office for two years. In 1528 he declined election as Capitano [military commander] at Verona, but in 1535 he accepted the post of Capitano at Padua. For his financial assistance to Venice in her war with the Turks he was named Procurator, 14 June 1537.

Although the three palaces of their father were not finally divided among the sons until after Cav. Proc. Giacomo's death, there must have been an earlier understanding that Cav. Proc. Giacomo and his descendants would receive the remains of the magnificent Malombra-Cornaro palace on the Grand Canal in S. Maurizio Parish, which had been destroyed by fire 15 August 1532. Cav. Proc. Giacomo's son Giorgio Cornaro [Giorgietto] (F-4) received the property in his deceased father's stead and erected Cą Cornaro della Cą Granda upon it, but the selection of Jacopo Sansovino as architect for the structure may have been accomplished by his father prior to his death.