"' Orgullo' - Proud," Santiago Gonzalez Cutre of Argentina told ABC News.
As Pope Francis addressed the faithful in his native tongue, there were cheers and tears of disbelief.
Francis, 76, the archbishop of Buenos Aires, is the first Latin American to lead the Catholic Church. He is also the first Jesuit to become pope.
According to Pew, the largest share of the world's Catholics - 39 percent - is located in Latin America and the Caribbean. In Argentina, 90 percent of all Christians are Catholic. The country has the 11th largest population of Catholics in the world.
Some said today that Francis' selection signaled a powerful change and the promise for a new future.
"I think he has a good base - especially Latin America has a large Catholic community down there so I think he will be impressive," said Tom Jackson, a San Diego resident studying abroad in Rome.
Victor Nunez de la Rosa, who was in Rome on vacation, said he'd never dreamed a fellow countryman would become pontiff.
"I still don't believe it," he said to ABC News.
"It is a celebration," said John Kukula of Dallas. "It is just phenomenal. Seeing something like this and the crowds and the sheer joy of people of all nations, literally, the Catholic Church is alive and well," said Kukula, who was in Rome visiting his daughter, Emma. "I think it is one of the best things that can be happening at this time - almost a new beginning. … That feelings of hope and a page turning."
And elsewhere, from Lima, Mexico City and Rio and especially Argentina, there was resounding emotion.
"For Catholics it's a great joy, such happiness that a representative of God on Earth has been elected," Manuel Moreno of Honduras told The Associated Press. "We hope that the whole world understands that nothing but Catholicism brings us closer each day to our creator."
ABC News' Cecilia Vega and The Associated Press contributed to this story.