[1][2] Pietro Leoni was born in Venice, Italy on 2 April 1637 and ordained a priest on 25 September 1667.
[2] On 14 November 1667, he was appointed during the papacy of Pope Clement IX as Bishop of Ceneda.
[1][2] On 20 November 1667, he was consecrated bishop by Pietro Vito Ottoboni, Cardinal-Priest of San Marco, with Carlo Stefano Anastasio Ciceri, Bishop of Alessandria della Paglia, and Francesco Grassi, Bishop of Nona, serving as co-consecrators.
[2] On 26 November 1691, he was appointed during the papacy of Pope Innocent XII as Bishop of Verona.
[1][2] He served as Bishop of Verona until his death on 17 December 1697.