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. When his father died in 1579, Giacomo began studying law. He moved to Rome, where in January 1601 he was made a clerk to the
Apostolic Camera. In May of that year he was appointed general commissioner of the army that
Pope Clement VIII sent to Hungary against the Turks. Serra had to organize the embarkation of the 9,000 pontifical troops in
Ancona and their subsequent journey from the disembarkation point to
Zagreb. In October, the papal mercenaries took part in the unsuccessful
Siege of Nagykanizsa. Serra sent regular reports to Rome on the operations. He and the surviving companies arrived in
Ravenna in early February. He then became
papal legate to
Ferrara in 16 September 1615, holding that post until his death. He issued regulations for the maintenance of public order, promoted economic activities, launched substantial public works both in the city and in the territory. He was Cardinal-protector of the
Canons Regular of the Lateran. In the meantime he became a cardinal priest on 28 September 1615 with the titulus of
Santa Maria della Pace. He took part in the papal conclaves of
1621 and
1623. Serra died on 19 August 1623 and was buried at Santa Maria della Pace. ==Art patron==