This article relies largely or entirely on a single source. (April 2017)
Early in his career he became Abbot of the monastery of Saints Cosmas and Damian in Zara. In 1448, he became a canon of the cathedral chapter of Padua Cathedral. He became primicerius of St Mark's Basilica in Venice in 1452. He later became a protonotary apostolic.
In the secret consistory of March 25, 1471, Pope Paul II secretly made Foscari a cardinal, but this was not published before the pope's death on July 26 and he was therefore not admitted to the papal conclave of 1471 that elected Pope Sixtus IV. In the consistory of December 10, 1477, Pope Sixtus IV made Foscari a cardinal priest; this was published on December 20 and Foscari given the titular church of San Nicola fra le Immagini. He arrived in Rome on March 12, 1478 and received the red hat on April 6, 1478.
On April 1478, he was named apostolic administrator of the metropolitan see of Spalato, a post he occupied until September 17, 1479. On April 15, 1481, he was named apostolic administrator of the see of Padua and occupied that post until his death. He left Rome for Padua on June 18, 1481 and returned to Rome on May 25, 1483.