The next course of study that Fr. George undertook, brought him to the Jesuit University in Beirut for seven years between 1958 and 1965. There, he specialized in Philosophy and Theology, plus Science and Mathematics for University teachers. Before leaving the Jesuit University, he became a Sub-Deacon in 1962, and a Deacon one year later.
On April 4, 1965, Deacon Athanasius Riashi was ordained a priest under the name of George. He elected to resume his studies, and accepted a scholarship to the Catholic University in Paris, France for French teaching. His summer in Paris ended, Fr. George assumed his duties as the director of St. John's Seminary, where he had studied in his youth. He remained at this first assignment for five years.
Prior to his ordination to the priesthood Fr, George was very active in the Boy Scouts for ten years, rising to their top ranks. Under his leadership and chaplaincy, the experience gained from the Boy Scounts was immensely helpful to him as he became rector of the seminary and his dealings with youth.
In all, during this period Fr. George started fifteen groups of Scouts, and in 1970, he was the General Chaplain for the Lebanese Guides, or Girl Scouts, For the 1969-1970 school year, he was the Director of St. Antonios High School in Kfarshima.
Fr, George was sent to Our Lady of Redemption Church in Detroit on December 1, 1971, to assist Archimandrite Agabios Riashi. As assistant pastnr for six years, he came to know both the church and the people very well, and was eventually made pastor on January 1, 1978. For these past years, Fr. George has been the driving force behind the Church Building Fund, and his strong leadership has encouraged parishioners to attend Divine Liturgy and become involved in church projects.
During his Golden Jubilee tour, His Beatitude Maximos V Hakim, on June 21, 1981, conferred the title of Archimandrite on Fr. George.
In January of 1983, after study to build a new church complex in Troy, Michigan, the former Harsia Junior High School in Warren, Michigan became available. All efforts were put into obtaining the school and twenty acres. The school has been converted to a community complex including: Church, Halls, Meeting Rooms, Pre-school and Rectory, all under one roof and his leadership.
On April 21, 1987, His Holiness. Pope John Paul 11 appointed our beloved Archimandrite George Riashi, the first Melkite Bishop of Sydney, Australia and New Zealand.
His Beatitude, Patriarch Maximos V Hakim ordained him to the Episcopacy on July 19, 1987, at St. John's Seminary in Konchara, Lebanon.