He was a son of the noblewoman Claudia Lomellini and her husband Antonio Maria Serra, deputy to Genoa's Nobile Vecchio Portico and a senator of Florence.
Serra had to organize the embarkation of the 9,000 pontifical troops in Ancona and their subsequent journey from the disembarkation point to Zagreb.
[3] In the summer of 1602, Serra was sent to Vienna with a contribution toward the payment of imperial infantry and cavalry for an anticipated campaign against Pest, which was seen as a base of operations to take nearby Buda.
Pope Paul V made him pontifical general commissioner for aid against the Turks in the Long Turkish War for which he recruited a regiment of German soldiers.
In 1610-1611 Serra commissioned extensive restorations and invited Discalced Augustinians from his hometown of Genoa to take over management of the church.