Ordained to the priesthood on 8 April 1962, Baïssari studied at the Holy Spirit University of Kaslik and obtained a title of Doctor of theology.
Pope John Paul II appointed him on 7 June 1991 titular bishop of Aradus and auxiliary bishop of Joubbé, Sarba and Jounieh.
His episcopal ordination occurred on August 3, 1991[1] by the hands of Maronite Patriarch of Antioch Cardinal Nasrallah Boutros Sfeir.
His co-consecrators were Roland Aboujaoudé, Auxiliary Bishop of Antioch, and Boutros Gemayel, Archbishop of Cyprus.
Baïssari retiring of his duties as auxiliary bishop on June 11, 2011, due to age-related reasons.