Following a formation at the Catholic Seminary of Beit-Jala (with the objective to become a priest), Haddad continued his studies of philosophy in Belgium, after which music composition in Jordan, Israel and England (teachers incl. George Benjamin).

In his works from 2004-2006, Haddad focused on achieving a synthesis between the Western and the Arabic traditions; this has been accompanied by a thorough study of the Arabic culture (until today). From 2007-2014, Haddad has been questioning the idea of forgetfulness of the Arabic culture using certain techniques which enable filtering memory while introducing elements of oblivion. From 2015 until now (especially with the aftermath of the Arab Spring), Haddad sees in musical composition (and in memory) an ethical responsibility sharing the pains of other human beings; this period is marked by a dark and melancholic character.

Haddad's music has been commissioned and performed by most prestigious international ensembles and orchestras in Europe, North America, Australia, Africa and Asia under the batons of Daniel Barenboim, Heinz Holliger, George Benjamin among others.

Haddad served as ‘composer-in-residence’ with numerous ensembles, orchestras and festivals. He was guest lecturer at many universities and was invited guest at many radio and TV stations.

Many honors rewarded Haddad's work including the French and German ‘Prix de Rome’ 2008-10, the deutsche Schallplattkritik Preis 2010, Nomination for the German Music Composers’ Prize 2013 and The Koussevitzky Music Foundation Commission- Library of Congress 2014.

His music can be heard on labels such as WERGO, NEOS and Ensemble Modern.