In the Argentine capital, hundreds of people gathered at the city's Metropolitan Cathedral. The country has the 11th largest population of Catholics in the world.
Back in Rome, Mayor Gianni Alemanno said he greeted the new pontiff's election with "wonderful emotion," lauding the "great simplicity" of his first remarks as pope.
Dolan, who had been considered a frontrunner entering the conclave, offered nothing but praise for the victor. The archbishop of New York described Pope Francis as "simple," "humble" and "sincere" at a news conference Wednesday evening, as evidenced by a gesture the new pontiff made when greeting cardinals after his election.
"He didn't go up on the platform and sit down in the special chair. He just stayed down and greeted each of us," Dolan said. "He's already won our hearts. He obviously won our hearts because he's the new pope."
ABC News' Kevin Dolak and Michael S. James contributed to this report.