Bishop Zgon Der Hagopian was born at Van in 1904. His entire family was murdered during the Genocide and he was sheltered in an orphanage in Baghdad, Iraq.

In 1922, he left the orphanage to enter the Seminary in Jerusalem.  His great-grandfather, grandfather and uncle were all priests.  After graduating in 1930, he remained at the Seminary as a teacher, until 1937 when he departed for Marseilles, France, to serve the Armenian community there until the Nazi takeover of France.  Bishop Zgon fled to the United States in 1940 on the last ship out of Marseilles, and served as a traveling pastor to various parishes in America during World War II.  He was sent to Chicago, where he studied at the McCormick Theological Seminary.

He later came to New York City, where he began editing the Armenian-language edition of The Armenian Church Monthly and served as pastor of the Holy Cross Church of Union City, New Jersey. He was then appointed pastor of the St. Gregory the Illuminator Church of New York City. He continued his studies at the Union Theological Seminary in New York City.

After a brief stay in San Francisco, during which he studied at Berkeley, he returned to Iraq as Primate of the Diocese of Baghdad.  He was elevated to the rank of bishop in 1958.  Following the 1958 revolution in Iraq, he left for Etchmiadzin. He was named Primate of Milan, Italy, in 1962. He was active there as an ecumenical representative of the Armenian Church to the Vatican.  He published many theological treatises on the sacrament of marriage and the celebration of Easter, which became a widely red book. In 1977, he retired to New York City, and he donated several items and books to the Diocese for its archive.

He passed away in March 1991.