He was friends with Scipione Borghese, the nephew of Pope Paul V, and was twice a candidate for election to the papacy, in the conclaves of 1621 and 1623.

Campori studied canon law in Lucca and Pisa, and moved to Rome after he was ordained a priest.

[1] In Rome, Campori served as the private secretary and major domo for Paul V's nephew Scipione Borghese.

He was opposed by the cardinals from Venice, who had been ordered to vote against him, and the French ambassador attempted to undermine his election.

Additionally, Pietro Aldobrandini, the nephew of Pope Clement VIII, opposed the election of any creation of Paul V, and was carried into the conclave on a litter despite being sick.