Most of the working life of Pagani was spent in Venice. He was already in Venice by 1677 and received the most influential of his artistic training there, most likely in the studio of Pietro Liberi. In 1685 a Paolo Pagani appears in the city's Registro dei Pittori and his most important Venetian works, among them Abraham and Isaac and Hagar and Ishmael in the Palazzo Salvioni, were painted around this time. Pagani traveled to Vienna in 1690 and, by 1692, had completed a commission for the Archbishop of Liechtenstein to paint one of the residential rooms in Kromerz and a series of large frescos in the monastery at Welehrad. He returned to Castello Valsolda, his native village on the Lake of Lugano, in 1697 to paint the Assumption of the Virgin in the Chiesa San Martino. After 1701, he painted two important altarpieces for the Capuchins of Chiusa and a Martyrdom of San Liborio in San Marco in Milan. He died in Milan in 1716 and his influence can be seen in the work of his Venetian pupil, Giovanni Antonio Pellegrini, the young Piazzetta, and Giulia Lama.