Reports of Qassem Suleimani's early life differ, and one U.S. counterterrorism official acknowledged that Washington's information about him is "sketchy."
He's believed to have come from humble roots in industrial Kerman province in Iran. One U.S. account says he was born in the Shiite holy city of Qom.
Suleimani joined the Revolutionary Guard Corps in the early 1980s to fight in the Iran-Iraq war, and he rose through the ranks until he was trusted to command one of 10 Iranian army divisions deployed to the border. One story has him crossing deep behind Iraqi military lines.
A U.S. intelligence official said that Suleimani is believed to have trained Arab fighters in Bosnia and to have gone to the Iran-Afghanistan border in 1996-97 amid seething tensions between Shiite Iran and the Sunni Muslim Taliban then ruling Afghanistan.
Shortly thereafter, Iran's supreme leader, Ali Khamenei, tapped him as the second person to command the Quds Force since its creation. In 2001, he assumed responsibility for Iraq policy, according to Iraqi politicians who work with him.
While he's not a household name in Iran, the Iranian military considers Suleimani a national hero. Photos of him are rare, and he's made only a couple of brief television appearances, mostly during patriotic events to honor those lost in the Iran-Iraq war. Still, one of his close Iraqi associates insists that "he's not a clandestine figure."
He's believed to be married and the father of four children, the U.S. counterterrorism official said.
Suleimani, widely described as a charismatic yet modest leader who never abuses his authority, has a portfolio that extends far beyond Iraq.
In the summer of 2006, when Israel fought the Shiite guerrillas of Hezbollah in a 33-day war, Suleimani joked to a friend that he'd "taken a break" from Iraq to command the Lebanese side of the battle, remembered the general's longtime Iraqi associate.
Detractors argue that he's a dangerous meddler who's willing to sacrifice the lives of innocent Iraqis for a proxy war with the United States. Allies respond that he's protecting Iran from a potential U.S. strike launched from Iraq; the Iranians know that Iraqi leaders are powerless to prevent such an action.
"He's courageous, he's committed, he has a vision for this region. He's a good interlocutor," the Suleimani associate said. "If the Americans want to stop things in Iraq, they'll have to talk to him."