He was born on 17 December 1936 in Buenos Aires, of Italian descent.
According to his official Vatican biography, he was ordained as a Jesuit in 1969 and went on to study in Argentina and Germany.
As a young man he had a lung removed because of an infection, but his health is currently said to be good.
He became a bishop in 1992 and Archbishop of Buenos Aires in 1998. At the 2005 conclave, he was seen as a contender for the papacy.
His election took many by surprise in his home city, where many had thought his age ruled him out, says the BBC's Marcia Carmo in Buenos Aires.
But any surprise soon gave way to the jubilant blaring of car horns on the streets.
As Cardinal Bergoglio, his sermons always had an impact in Argentina and he often stressed social inclusion, indirectly criticising governments that did not pay attention to those on the margins of society.
Francesca Ambrogetti, who co-authored a biography of him, told Reuters news agency that part of his public appeal lay in his "sober and austere" humble lifestyle.
In Buenos Aires, he lived in a simple flat. When in Rome, he often preferred to keep his black robe on and is also said to have re-used the cardinal's vest used by his predecessor.
According to BBC