ROME — Cardinal Jorge Mario Bergoglio of Argentina, a humble pastor and Jesuit known for his care of the poor, was elected the 266th pope of the Roman Catholic Church on Wednesday. He chose the name Francis.
He is the first non-European pope in modern times and the first ever from Latin America, now home to 42 percent of the world’s Catholics. He is also the first member of a religious order elected since the early 19th century.
As a jubilant crowd of 100,000 in St. Peter’s Square cheered under bright lights and spitting rain, Francis, speaking in Italian, his bearing serene, accepted the duty thrust upon him.
“You know that it was the duty of the conclave to give Rome a bishop,” he said. “It seems that my brother cardinals have gone to the ends of the earth to get one. . . . I thank you for your welcome.”
His election was a surprise. Many in the crowd turned to one another in puzzlement when his name was announced in Latin from a red-curtained window high above the square. Although he was said to have finished second to Joseph Ratzinger in the last conclave in 2005, he was not thought to be a front-runner this time.
He considers social outreach, rather than doctrinal battles, to be the essential business of the church. Catholics are still buzzing over his speech last year accusing fellow church officials of hypocrisy for forgetting that Jesus Christ bathed lepers and ate with prostitutes.
While his selection was historic, Francis appears unlikely to substantially alter the theological trajectory of the church. Much like his predecessors, Benedict XVI and John Paul II, he is a strident foe of abortion, contraception, and same-sex marriage, having waged a forceful but ultimately unsuccessful battle against same-sex marriage in his homeland.
Across the planet, Latin Americans burst into tears and jubilation at news that the region finally had a pope to call its own.
‘‘It’s a huge gift for all of Latin America,’’ said Jose Antonio Cruz, a friar at St. Francis of Assisi Church in Old San Juan in Puerto Rico. “We waited 20 centuries. It was worth the wait.’’
New popes traditionally bless the vast sea of people below them; Wednesday night, Francis asked the people to bless him first. “Before the bishop blesses his people, I ask you to pray to the Lord that he will bless me,” he said. “The prayer of the people asking the blessing for their bishop. Let us make, in silence, this prayer: your prayer over me.”
For a few moments, a square that had echoed with tens of thousands of voices grew quiet.
Cardinal Timothy Dolan of New York, who spoke with reporters later in the evening, said the new pontiff chose his name in honor of St. Francis of Assisi, known for reform and care for the poor.
Cardinal Bergoglio is known for riding the bus to work, cooking his own meals, and regularly visiting the slums around Buenos Aires.
Eric LeCompte, who directs Jubilee USA, a religious organization that works on financial reforms to help the poor, said the pontiff has a deep sense of solidarity with the poor and refers to extreme poverty as a violation of human rights.
“When times were tough” in his native Argentina, “he made sure people didn’t forget the poor and vulnerable,” LeCompte said.
Bergoglio’s elevation to the papacy was greeted with wariness in some quarters. Marianne Duddy-Burke — executive director of DignityUSA, an advocacy group for gay Catholics — lamented that in Argentina, Bergoglio “made some very harsh and inflammatory statements about lesbian, gay, bisexual, and transgender people.”
“We recognize that sometimes this new job on which he embarks can change the man called to it,” she said. “We invite him to take the time to learn about our lives, our faith, and our families before he makes any papal pronouncements about us, and we stand ready to enter into dialogue with him at any time.”
John F. Schwaller, author of a history of the Catholic Church in Latin America, said that Francis’s selection marks a signal moment in the life of the church and its 1.2 billion adherents worldwide. “The fact that someone from the region has been chosen as pope is going to be seen as a major recognition of interest in the issues of the Third World, Latin America specifically,” he said.
He noted that because of the pope’s ancestry, some early detractors of Francis’s have called him an Italian pope who happened to be born in Argentina. But Schwaller said that Bergoglio was born and raised in Argentina and has spent most of his life there.
Schwaller also said that with his choice of name, Francis may be acknowledging the legacy of liberation theology, but in a less political way than the liberation theologians of the 1960s and 1970s. Followers of liberation theology believe Catholicism should be viewed through the prism of freedom from economic and social oppression.
But Francis has been the target of criticism by some in Argentina who allege that he failed to intervene during the country’s Dirty Wars of the 1970s, when thousands were tortured and murdered. Those critics says he was aware of atrocities but would not stand up to the dictatorship. Francis has rejected that assertion, saying he hid people on church property during that era.
Cardinal Sean P. O’Malley, archbishop of Boston, visited Bergoglio on a trip to Buenos Aires in December 2010, O’Malley’s priest secretary, the Rev. Jonathan Gaspar, said.
O’Malley, a Capuchin Franciscan who was considered a contender for pope, has much in common with the new pontiff. In addition to membership in a religious order, a preference for simplicity, and concern for the poor, O’Malley is fluent in Spanish and Portuguese.
O’Malley did not grant interviews last night, opting to spend an extra night at the Domus Sanctae Marthae, the Vatican residence where the cardinals stayed during the conclave. But Gaspar said the Boston cardinal was thrilled with Bergoglio, calling him someone who is “not just concerned about the poor, but his pattern of living eschews the trappings of power.”
Dolan said he was shocked, as he got off the minibus ferrying cardinals from the Apostolic Palace to the Domus Sanctae Marthae, that Francis had skipped a chance to ride in the waiting popemobile and hopped aboard the minibus, musing that he needed to drop by his hotel the next morning and settle his bill.
Francis told the other cardinals he plans to visit his predecessor, Benedict XVI, at the Castel Gandolfo on Thursday, Dolan said. He also plans to visit the Basilica of St. Mary Major in Rome to pray.
At 76, Bergoglio has slowed a bit with age and is feeling the effects of having a lung removed due to infection when he was a teenager.
The Rev. Thomas Worcester, a historian at the College of the Holy Cross who has written about the papacy, said the cardinals clearly felt no pressure to pick someone younger. “I think Benedict’s resignation opened the way,’’ Worcester said. “He could do eight, nine, or 10 years and resign if he has health problems.’’
The selection was surprisingly quick, coming after only three votes produced black smoke Tuesday evening and Wednesday morning.
At 7:06 p.m. Wednesday, when the smoke first appeared over the Sistine Chapel, a few despairing cries of “it’s black” rang out among the tens of thousands assembled on St. Peter’s Square. But not for long. As the smoke billowed white against the evening gloom, cheers rang out across the rain-soaked square.
An echelon of Swiss Guards marched into the square and assembled at the foot of St. Peter’s Basilica, under the red-curtained balcony. Cheers erupted when those curtains parted at 8:12 p.m., and Cardinal Jean-Louis Tauran walked out and proclaimed, in Latin, “I announce to you a great joy: We have a pope.”
As soon as he announced that the new pontiff had chosen the name Francis, the crowd began to chant, “Francesco, Francesco.”
Soon thereafter, Francis appeared on the balcony to a thunderous ovation and gave a slight, shy wave.
He led the crowd in the Lord’s Prayer, Hail Mary, and Gloria before asking his followers to say a silent prayer of blessing for him.
And then the pontiff finished his address with a wish of “rest well,” and the square rumbled back to life.
David Filipov and Peter Schworm of the Globe staff, and Globe wire services contributed to this report. Lisa Wangsness can be reached at lwangsness@