Having entered the Seminary of Saint Anne in Rabweh in 1935, he finished his studies there and was ordained to the priesthood at the Melkite diocese in Beirut on 26 June 1948.
Subsequently, Haddad filled a teaching post, became secretary at the Archbishopric of Beirut and pastor at the parish of Saint John Chrysostom.
[3] In the ten years before the outbreak of the Lebanese Civil War (1975-1990), Haddad had a new seat of the archeparchy constructed and the historical Cathedral of Saint Thomas repaired.
When Israel's invasion of Lebanon started on 6 June 1982, Haddad reportedly succeeded in temporarily halting the attack of an Israeli Defense Forces (IDF) tank column in a bold appeal to its commander, mediated by a Swiss delegate of the International Committee of the Red Cross (ICRC), to evacuate the civilian population to the beaches.
"[2]During his tenure, Haddad was co-consecrator of: "He died 30th December 1985, after a long and painful illness which had come upon him suddenly and which he bore with loving resignation to the will of the lord.