[1] He was the great-grand-nephew of Gian Facchinetti, who took the papal throne in 1591 as Pope Innocent IX.

Upon his return, he was elevated to Cardinal on 13 July 1643 by Pope Urban VIII[2] and was installed as Cardinal-Priest at the Santi Quattro Coronati basilica.

Facchinetti was popular with the other cardinals of the college and there was discussion, according to contemporary John Bargrave,[3] that he might be considered papabile - that is, appropriate for election as pope.

His brother, for example, was appointed as commander of the militia by Pope Innocent X during the second War of Castro.

At the death of Francesco Barberini (10 December 1679) he became Dean of the College of Cardinals and in the consistory of 8 January 1680 Innocent XI appointed him Bishop of Ostia e Velletri, Secretary of the Roman Inquisition and administrator of the Apostolic Chancery, positions he held until his death.