VATICAN CITY (AFP)
Prevost became the first pope from the United States on Thursday, picking the papal name Leo XIV after cardinals from around the world elected him leader of the world's 1.4 billion Catholics.
Tens of thousands of people packed in St Peter's Square cheered as Prevost appeared on the balcony of St Peter's Basilica, waving with both hands, smiling and bowing.
"Peace by with you," he told the crowds.
White smoke from the Sistine Chapel had billowed into the sky on the cardinals' second day of voting to announce his election in a secret conclave, while the bells of St Peter's Basilica and churches across Rome rang out.
Crowds of people rushed towards the square to watch the balcony of the basilica, which has been fitted out with red curtains for the first address to the world by the 267th pope.
The new pontiff, who succeeds Argentine reformer Pope Francis, was introduced in Latin with his chosen papal name.