The 76-year-old leader, who served as the archbishop of Buenos Aires, is the first pope to take the name in honor of St. Francis of Assisi, revered among Catholics for his work with the poor.
The pontiff is a follower of the church's most social conservative wing. As a cardinal, he clashed with the government of Argentine President Cristina Fernandez de Kirchner over his opposition to gay marriage and free distribution of contraceptives.
He was runner-up in the 2005 papal conclave, behind then-Cardinal Joseph Ratzinger.
The new pope brings together the first and the developing worlds. Latin America is home to 480 million Catholics.
Francis' first public appearance as pope -- when he appealed for the crowds to pray for him before he gave a blessing -- suggested a "different pastoral style" in comparison with the more academic approach of Benedict, said Lombardi.
Francis is someone who has had "a day-to-day link with the population and ordinary people" during his many years at the head of a large diocese in Buenos Aires, he said.
He also sought to dampen concerns prompted by media reports that the new pope has only one lung.
Although Francis had part of one lung removed when he was a young man, the whole lung was not removed and the new pope is in good health, Lombardi said.
CNN iReporter Cesar Sotolongo in Lima, Peru, said the election of a Latin American pope, particularly from the Jesuit order, marked "a new chapter" for the Catholic Church.
Originally from Florida, Sotolongo also has his own advice for Francis: "The pope should shape the church with what he has been doing during his career (as an example)," he said. "Stay in contact with the people, communicate clearly, promote the unification of faith and ... represent the word of Jesus."
A Jesuit pope
Born in Buenos Aires to an Italian immigrant father, Francis is known for his simplicity.
Details given by Lombardi on Thursday of Francis' first hours as pope reinforce that impression -- one which may go down well with his global flock, many of whom live in poverty or are feeling the squeeze of austerity.
Francis stood, rather than sitting on a throne, to receive the oath of allegiance from his fellow cardinals after his election, and for his appearance on the balcony wore just a white cassock and a simple cross, eschewing gold or jewels, Lombardi said.
Also, on the ride back from the Sistine Chapel to the Santa Marta residence, he declined the papal car that had been prepared for him and instead took the bus with other cardinals, Lombardi said.
And Francis thanked the other cardinals at dinner, joking, "May God forgive you for what you have done," Lombardi said.
Francis will remove the seals from the official papal apartments Thursday but will not move in until renovations are complete, he added. The new pontiff will live in a suite at the Santa Marta residence until the papal apartments are ready.
In Buenos Aires, Francis chose to live in an apartment rather than the archbishop's palace, passed on a chauffeured limousine, took the bus to work and cooked his own meals.
He was ordained by the Jesuits in 1969. He became co-archbishop of Buenos Aires in 1997 and sole archbishop of that city one year later.
He was made a cardinal in 2001 and served as president of the Argentine bishops conference from 2005 to 2011.
As a Jesuit, Francis is a member of the Society of Jesus, one of the biggest and most important orders in the church.
Jesuits are recognized for their exceptional educational institutions and focus on social justice.
"Jesuits are characterized by their service to the church ... but trying to avoid positions of power," said Lombardi, the Vatican spokesman, who is also a Jesuit. "I am absolutely convinced that we have a pope who wants to serve.
"His election was the election of a rejection of power."