[5][6] He was a visiting fellow (2013-2015) then senior assistant professor (2015-2018) at the Sultan Omar Ali Saifuddin Center for Islamic Studies, Universiti Brunei Darussalam.
[10] In 1976, his father died during the Lebanese Civil War and his family was forced to flee Lebanon for the United Kingdom where Haddad completed high school.
[10][12] Later his family moved to the United States where Haddad attended Columbia College in New York City and graduated with a Bachelor of Arts degree.
Haddad recalls that this event had a significant impact on him and made him feel envious: “Here was an American embracing the religion of my people - the Arabs - and the religion I felt attached to.”[12][10] During a year he spent in Paris on a scholarship, Haddad bought a complete set of tapes of the recitation of the Quran.
[12] In 1991,[13][7] he went to a Muslim student group at Columbia University and pronounced the Shahada, thereby formally converting to the Hanafi Sunni branch of Islam.
[12][10] Shortly after his conversion, Haddad met Shaykh Hisham Kabbani of Tripoli[12][10] who introduced him to the ways of the Naqshbandi Spiritual Order (tariqa).
[11][17] Jonathan A. C. Brown has noted Haddad to be an orthodox Sunni who has penned abrasive polemics against Salafism and mounted vigorous defense of traditional Islamic law.
[17] He has also written a critique of Deobandi scholar Mufti Taqi Usmani's fatwa against the celebration of Muhammad's birthday (Mawlid).