U.S. sources have confirmed that ISIS leader Abu Bakr al-Baghdadi is dead, apparently using a suicide vest to kill himself during a U.S. raid on a compound in northwest Syria, marking the latest successful operation against the once-powerful group that at one point controlled portions of Iraq and Syria.

But who was the man whose death triggered worldwide headlines and a giant blow to ISIS?

Al-Baghdadi, whose real name is Ibrahim ibn Awwad Ibrahim Ali al-Badri al-Samarrai, took over ISIS in 2010 after previous leader Abu Omar al-Baghdadi was killed.

ISIS LEADER AL-BAGHDADI CONFIRMED DEAD AFTER APPARENT SUICIDE DURING U.S. OPERATION: SOURCES

Born to a lower-middle class family in Samarra in the Sunni Triangle north of Baghdad in 1971, al-Baghdadi was part of a religiously conservative family, but was believed to have been radicalized decades later.

Earlier in his life, he earned a PhD in Islamic jurisprudence from what was then known as Saddam University, later renamed Islamic University of Baghdad after the U.S. ousted Saddam Hussein. According to Fawaz A. Gerges’ book “A History of ISIS,” the “consensus among people who knew Baghdadi” is that the “turning point in his radicalization” was when the U.S. invaded Iraq in 2003.

Al-Baghdadi was captured by U.S. forces in February 2004. He was released that December along with other militants who were believed to be “low level” threats. After he was released, he reportedly told an American prison guard that he “will find you … anytime and anywhere…here or New York.”

In 2006, al-Baghdadi joined ISIS, which at the time was led by founder Abu Musab al-Zarqawi. The group's military leaders were mostly former generals who served under Saddam Hussein's Baathist regime.

At its height, ISIS controlled a swath of Iraqi and Syrian territory roughly the size of Ohio. The self-declared caliphate was defeated in Iraq in 2017, and fell in Syria when it lost its territory in March 2019.

A shadowy leader, al-Baghdadi was the world's most wanted man, with a $25 million price on his head.

Al-Baghdadi was known to release audio messages encouraging ISIS and its supporters. A recording released just last month called on members of the extremist group to free detainees and women held in jails and camps by any means necessary. It was al-Baghdadi's first known public statement in roughly five months.

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In a 30-minute recording released by the group’s media wing, the ISIS leader asked: "How can a Muslim enjoy life?" when Muslim women are held in camps he called "prisons of humiliation run by Crusaders and their Shiite followers."

Despite recent battlefield defeats, sleeper cells have continued to launch attacks in both Iraq and Syria. For years, terror attacks around the globe were inspired by ISIS and its ideology. In his September message, al-Baghdadi encouraged his followers to keep the movement alive, telling “soldiers and supporters of the Caliphate everywhere” to avoid deviation and asking Allah to grant ISIS victory.

Fox News' Bradford Betz and The Associated Press contributed to this report.