On 2 December 1979, Arbach was ordained a deacon and received on 24 August 1980, the ordination to the priesthood in the Basilian order.
Arbach was head of the Episcopal seminary of Zahle and Furzol and studied psychology at the National University in Lebanon.
In 2004 Arbach went back and was in the diocese of Zahle and Furzol rector of the Oriental College, where he taught Arabic, French and Spanish.
Arbach was in October 2010, participant at the Special Assembly of the Synod of Bishops (Catholic) for the Middle East in Rome.
On June 23, 2012, Abdo Arbach was appointed archbishop of the Melkite Greek Catholic Archeparchy of Homs, Hama and Yabroud.