[2][3] Carlo Gaetano entered in the clerical state in his youth, he studied in Rome at the Pontifical Roman Seminary and on 10 July 1698 he earned a doctorate in utroque iure at the University of Pavia.

[4] In 1703 he moved to Rome where he entered in the administration of the Papal States: in 1705 he became referendary of the Tribunals of the Apostolic Signature, on 10 December 1706 he was appointed Vice-legate of Romagna, a position he kept until 1709.

[4] Carlo Gaetano was ordained priest on 31 October 1717 and he was appointed Titular archbishop of Chalcedon on 6 December 1717, being consecrated bishop on 23 Jan 1718 by Cardinal Ferdinando d'Adda in Rome.

[6] Due to his cardiac problems, he could make a pastoral visit only to the town of Abbiategrasso, but he convened all the vicars of the diocese on Milan on 7 June 1742.

His funeral service was held on 21 January 1743 and his remains were buried in the North transept of the Cathedral of Milan.