Argentina's Jorge Mario Bergoglio was elected Pope Francis on Wednesday, becoming the first Latin American pontiff in an astonishing decision seen as a signal of greater openness for a troubled Roman Catholic Church.
The 76-year-old railway worker's son emerged smiling on the balcony of St Peter's Basilica to cries of "Long live the pope!" and devoted his first prayer to his predecessor Benedict XVI as tens of thousands of pilgrims cheered.
The first non-European pope in nearly 1,300 years of Church history called for "fraternity" among the world's 1.2 billion Catholics after the scandal-ridden papacy of his predecessor Benedict XVI.
"It seems that my brother cardinals have gone to the ends of the earth (to find a pope)," Francis said, referring to his native Argentina, which erupted in celebrations at his appointment.
"Now, we take up this journey... A journey of fraternity, of love, of trust among us," he said.
World leaders hailed the election of a pope seen as a moderate conservative who chose to name himself after the ascetic St Francis of Assisi.
US President Barack Obama said Bergoglio was "a champion of the poor and the most vulnerable among us."
Argentina's President Cristina Kirchner wished her fellow countryman "a fruitful pastoral mission."
Justin Welby, the new leader of the world's Anglicans, said he was looking forward to "walking and working together" with the new pope.
Vatican spokesman Federico Lombardi said the choice by 115 cardinals in a secret conclave in the Sistine Chapel had "widened the perspective of the Church" and he hailed their boldness in "crossing the ocean".
Sergio Rubin, religious writer for the Buenos Aires-based newspaper Clarin, said that, like pope John Paul II, Bergoglio was "conservative at the level of doctrine, and progressive on social issues".
The election was also being seen as recognition of a thriving faith in Latin America, home to 40 percent of the world's Catholics while Catholicism is in decline in its traditional bastion in Europe.
"I can't believe it! An Argentinian pope!" said Silvia Pastormerlo, a 50-year-old from Argentina who was celebrating in the rain-soaked St Peter's Square.
Julio Cesar Attaremo, 42, waving an Argentinian flag in the square, said: "He's very humble and he's someone who really goes out to the people.
"We're very happy and proud. Not just for Argentina but for the whole of South America," he said.
The papal Twitter account @pontifex announced the election with a simple phrase in Latin: "Habemus Papam Franciscum" ("We Have Pope Francis").
There had been growing calls both within and outside the Roman Catholic Church for the next pope to be from the southern hemisphere for the first time but Bergoglio was never considered one of the frontrunners.
Some bookmakers had ranked him 40th on their list of favourites and had not even taken bets on Francis.
-- 'Solid and pragmatic' --
The new pope is believed to have been the runner-up at the conclave in 2005 that elected Benedict -- although cardinals taking part are sworn to secrecy on pain of excommunication.
The Vatican said his formal inauguration mass would be on Tuesday next week -- a significant date in the Catholic calendar because it is the Feast of St Joseph, patron saint of the universal Church.
The Argentinian of Italian descent -- the 266th pope -- told the faithful he would visit a shrine to the Virgin Mary in his first act as pope on Wednesday, with the Vatican saying this could be the basilica of Santa Maria Maggiore in Rome.
White smoke earlier billowed from the chimney on the Sistine Chapel and the bells of St Peter's Basilica rang out, signalling the election had taken place after five rounds of voting -- one more than when Benedict was elected in 2005.
Vatican expert Bruno Bartoloni said Bergoglio was "a solid, pragmatic, efficient man who can do something concrete, notably to reform the Roman Curia" -- the internal workings of the Vatican.
"On the social level he is probably very open, while probably conservative on moral issues," he said, describing a duality typical of the cardinals named by Benedict and his predecessor John Paul II.
Benedict's eight-year papacy was riven by scandals and the new pope will face immediate challenges -- chief among them stamping his authority on the Vatican machinery and trying to bring back a Catholic flock that is deserting churches across the West.
The scandal of hushed-up sexual abuses of children by paedophile priests going back decades has also cast its shadow over the conclave.
The 85-year-old Benedict's style was often seen as too academic and he was never as popular as John Paul II.
But Benedict broke with tradition, becoming the first pope to step down since the Middle Ages. The German theologian has said he will retire to a former nunnery inside the Vatican.
The Vatican said Francis had already called his predecessor and would meet with him soon.
In one of his last acts as pope, Benedict issued a decree allowing cardinals to bring forward the date of a conclave in the event of a pope's resignation -- a move seen by many as potentially setting a precedent for ageing pontiffs in the future.
Vatican experts said the prospect of future resignations could have encouraged the cardinals to elect an older candidate in the knowledge that they could step down if their strength fails.