Pope Leo XIV has been diagnosed with lung cancer. Here's what to know about the first American pope.

Robert Prevost was born in Chicago in 1955.

He's 71 years old and was ordained to the priesthood in 1982. He has two brothers.

He's also a citizen of Peru, where he was first assigned in 1985, and later served as the Bishop of Chiclayo.

He has a doctorate and is multilingual.

He studied at Villanova University and the Catholic Theological Union of Chicago. In 1984, he obtained his Canon Law licentiate, and in 1985, he defendedhis doctoral dissertationat the Pontifical University of Saint Thomas Aquinas.

Pope Leo XIV speaks English, Spanish, Portuguese, Italian, and French.

Pope Francis appointed him to one of the Vatican's most influential positions.

In 2023, the then-pope appointed then-Bishop Prevost as Prefect of the Dicastery for Bishops and president of the Pontifical Commission for Latin America, which plays a key role in bishop nominations.

In 2024, Pope Leo said in an interview with Vatican News that a "bishop is not supposed to be a little prince sitting in his kingdom, but rather called authentically to be humble, to be close to the people he serves, to walk with them and to suffer with them."

A group of 133 cardinals elected him during the May 2025 conclave.

The process is known as the conclave. It took two days and four rounds of voting for the cardinals to agree on a new pope, per the AP.

Before the conclave, the National Catholic Reporter wrote that it was unlikely the US cardinal would become pope because of political implications. Yet Cardinal Prevost was considered a contender by others, especially as the week went on, ABC News reported.

Pope Leo XIV gave his first message on May 8, 2025.

Speaking from the balcony of St. Peter's Basilica, Pope Leo XIV said, "Peace be with all of you" in his first words in his new role. He spoke in Italian and then Spanish.

"My experience of Cardinal Prevost was that he's not a showboat," Father Mark R. Francis, who worked with Pope Leo in the past, told CBS News in 2025. "He's very calm, but extremely intelligent, and extremely compassionate."

Since becoming pope, he has begun putting his stamp on the Church.

He canonized Carlo Acutis and Pier Giorgio Frassati in September 2025, and made his first foreign trip to Turkey and Lebanon in November and December of that year.

His first encyclical, a letter written by the Pope for guidance, addressed AI.

Business Insider's Joshua Nelken-Zitser identifiedthree main takeawaysfrom the encyclical: the power of AI should not be monopolized by a small group; AI developers should ensure that what they are cultivating "is a genuine good";and warnings that AI could lead to mass unemployment.

In addition to the encyclical, Pope Leo XIV has spoken about AI multiple times, includinga recent addressto artists and curators in which he said, "We urgently need to distinguish human art from what is produced by machines."

Pope Leo XIV was diagnosed with lung cancer on October 13, 2026.

The pope underwent an operation to remove the lower lobe of his right lung, the Holy See press office said in October. It added that the surgery was successful with no complications.

The operation confirmed a previously suspected lung cancer diagnosis.

On Wednesday, the Holy See press office said the "night passed calmly" for the pope.