He was the highest ranking American agent of Middle Eastern and North African descent ever employed by the Federal Bureau of Investigation as of 2009, as a Unit Chief in the FBI Counterterrorism Division.
[citation needed] Prior to holding this position, Youssef coordinated the national counterterrorism investigation into the Islamic Group, the organization responsible for the first World Trade Center bombing.
After obtaining the DCI award, he was selected by the former FBI Director Louis Freeh to head of the FBI’s overseas office with responsibility for Saudi Arabia and the contiguous Gulf States, including UAE, Kuwait, Oman, Yemen, Bahrain and Qatar.
According to an FBI report drafted in 2000, within three months of his arrival in Saudi Arabia Youssef's "efforts led to the establishment of direct communications with senior officials of the Mabahith [Saudi Arabia's security service] which had previously been unavailable to US Embassy personnel."
These contacts were crucial in establishing a first-ever meeting between then-FBI director Louis Freeh and Saudi officials.