Abu Ghaith first gained attention during the 1990-1991 Iraqi invasion and occupation of Kuwait, his sermons denouncing the occupation and Iraqi President Saddam Hussein gaining him some degree of popularity amongst the Kuwaiti people. Following the defeat of Iraq, he turned his attention towards the Kuwaiti government and royal family, denouncing the 1962 constitution and demanding the institution of Sharia law. The Kuwaiti government subsequently removed him from the mosque and banned him from giving sermons, and he became a high school teacher of religion.
In June 2000 he left Kuwait for Afghanistan, where he met Osama bin Laden and joined his Al-Qaeda organization. His affinity for public speaking and comparative youth put him at the head of Al-Qaeda's attempt to widen its appeal from ultra-conservative and mostly elderly clerics to the general population and especially the youth of majority-Muslim countries; in this capacity, he quickly became the organization's spokesman.
He rose to worldwide attention following the September 11, 2001 terrorist attacks. In October 2001 he appeared on two widely-circulated videos (first broadcast on al-Jazeera television) to defend the attacks and threaten reprisals for the subsequent US invasion of Afghanistan, saying "Americans should know, the storm of the planes will not stop ... There are thousands of the Islamic nation's youths who are eager to die just as the Americans are eager to live." These statements caused the Kuwaiti government to strip him of his citizenship.
His whereabouts, as he moved around to escape capture by the United States in the following months, are unclear. In July 2003, a Kuwaiti minister announced that the Iranian government had offered to extradite Abu Ghaith to Kuwait, but that Kuwait had refused the offer. It is unclear (as of July 2003) whether he is currently in Iranian custody, or indeed in Iran at all.