He then obtained a doctorate in both canon and civil law on 4 November 1922. Coussa was ordained a priest of the Basilian Alepian Order on  20 December 1920 in Rome by Isaias Papadopoulos, titular bishop of Grazianopoli, assessor of the Sacred Congregation of the Oriental Church.
He later earned doctoral degrees in both canon and civil law on 4 November 1922. Coussa was ordained a priest of the Basilian Alepian Order on 20 December 1920 in Rome by Isaias Papadopoulos, titular bishop of Grazianopoli, assessor of the Sacred Congregation for Eastern Churches.