 Giovanni Battista Paggi was born in Genoa, Italy in 1615 and ordained a priest in the Barnabite Order.On 14 June 1655, he was appointed during the papacy of Pope Alexander VII as Bishop of Brugnato.On 20 June 1655, he was consecrated bishop by Giulio Cesare Sacchetti, Cardinal-Bishop of Frascati, with Francesco Antonio Sacchetti, Bishop of Troia, and Giacinto Cordella, Bishop of Venafro, serving as co-consecrators.