Pope Leo XIV was elected as the Catholic Church's 267th leader on Thursday.
The temporary chimney atop the Sistine Chapel released a plume of white smoke on Thursday evening local time, signaling that the 133 cardinals working inside had reached a two-thirds majority to elect a new pope for the Catholic Church.
American Cardinal Robert Prevost was shortly thereafter announced as the 267th pontiff. He chose the name Leo XIV, a senior cardinal deacon announced.
The 69-year-old Chicago native is the first American pope and is seen as a diplomat in the church.
"This is the first greeting of the risen Christ. May the peace be with you," Leo said in Italian in his first remarks as pope. "This is the peace of the risen Christ."
Tune in to "The American Pope: Leo XIV," a special edition of "20/20," streaming now on Hulu and Disney+.
On his first full day after being elected the 267th pontiff, Pope Leo XIV is now celebrating his first mass as pope at the Sistine Chapel in Vatican City.
The service started with a choir singing an antiphon from Psalm 46 and it is being conducted in multiple languages.
An estimated 150.000 people filled St. Peter's Square on Thursday evening to welcome the new pope, the Italian Department of Civil Protection told ABC News.
Pope Leo XIV has several events scheduled over the next few days, according to the Vatican.
On Friday, Leo will celebrate mass in the Sistine Chapel at 11 a.m. local time, Matteo Bruni, director of the Holy See Press Office, told journalists in a short briefing Thursday evening.
Leo will recite the Regina Coeli prayer from the central balcony of St. Peter’s Basilica on Sunday at noon and on Monday at 10 a.m., Leo will give an audience to all accredited journalists and media workers, in which he is expected to give a speed.
A friend and former classmate of the newly elected Pope Leo XIV is singing the new pontiff's praises has he ascends as the leader of the Catholic Church.
The Rev. Mark Francis described the pontiff as "low key," focused, "very thorough" and "an extremely good listener." He expects his friend to "continue along the lines of Pope Francis" but bring his own style.
"I am still amazed at the results of this election -- very happy, mainly because this humble, good person is going to be leading the church," Francis said.
Francis met Leo, then Robert Francis Prevost, in 1977 at the Catholic Theological Union in Chicago, where they were both seminararians -- or religious students -- and in the same theological reflection group. During discussions, Leo could always be counted on to contribute thoughtfully to the conversations, Francis said.
Throughout their decades-long friendship, Francis has known the new pope as "Bob."
"It's going to take me a while to get used to calling him Pope Leo," Francis said.
James Priestley has known Pope Leo XIV for decades, rooming with him in high school and attending Villanova University at the same time. He told ABC News it was "quite a shock" to learn his longtime friend had become the new pope.
At the same time, he said, "If you were going to imagine somebody to become pope, it would be Bob."
"He was a very religious guy, very bright guy and very organized," Priestley said. "I have no stories about him being bad in any way, shape or form from school."
Priestley said he saw his friend a few times over the years, but the pope was mostly out of the country. When Leo returned to the Chicago area last summer, Priestley said he got to see him at an event at St. Jude’s Church in New Lenox.
"I was very impressed," he said. "His public speaking ability is very, very good."
He said he also reconnected with Leo at that time at a pizza place in Homewood.
Priestley imagines Leo will make it back to the area again, this time as pope.
"I'm sure he'll be back to Chicago because this is his home base," he said. "This is where his brother Augustinians are located."
