Abu Marzook was born in the Gaza Strip and traveled to the United States to earn his PhD in Industrial Engineering. While living in the U.S., Marzook became involved with Hamas, a Palestinian militant Islamic group. Marzook was elected as Chairman of the Hamas Political Bureau and subsequently moved to Jordan (1991) where he was suspected of planning numerous terrorist attacks. In 1995, Marzook was arrested in the U.S., and Israel requested his extradition. Ultimately, Israel decided not to extradite Marzook and he was deported to Jordan, but was later deported in 1999.