Jorge Mario Bergoglio of Argentina was elected pope on Wednesday to lead the Roman Catholic Church, a prelate announced to huge crowds gathered in St. Peter's Square.
He took the name Pope Francis, the cardinal said.
Cardinals elected Bergoglio on just the second day of a secret conclave to find a successor to Pope Benedict, who abdicated unexpectedly last month.
Francis delivered his first blessing to a huge crowd in St Peter's Square on Wednesday night, asking for the prayers of "all men and women of good will" to help him lead the Catholic Church.
Francis, speaking Italian with a slight Latin American accent, joked with the crowd before delivering his blessing, saying: "As you know the duty of the conclave is to give Rome a bishop. It seems that my brother cardinals went almost to the end of the world."
Reporting by Crispian Balmer and Philip Pullella