Caroldo trained as a notary and took a job in the chancery in 1496. In a document he wrote on 15 September 1511, he records how he had been part of diplomatic missions to England, Spain, the Ottoman Empire and various states in Italy. He was the secretary of Ambassador Andrea Gritti during the negotiations that ended the Ottoman–Venetian War of 1499–1503. A report he wrote on this mission, dated 30 September 1503, was included by Marino Sanudo the Younger in his "Diarii".