Vaughan was ordained a priest in Rome in the chapel of the Pontifical North American College on December 8, 1951, for the Archdiocese of New York by Archbishop Martin John O’Connor.[2] He received a Licentiate in Sacred Theology from the college in 1952, then a doctorate from the Pontifical Gregorian University in Rome in 1954.[1]
Returning to New York, Vaughan in 1956 was named to the faculty of St. Joseph's Seminary where he taught theology. He was named rector of St. Joseph's in 1973.[1]
Auxiliary Bishop of New York
On May 24, 1977, Pope Paul VI named Vaughan as an auxiliary bishop of New York and titular bishop of Cluain Iraird. He was consecrated bishop on June 29, 1977, at St. Patrick's Cathedral in Manhattan by Cardinal Terence Cooke.[2]
In December 1988, Vaughan was convicted of disorderly conduct at a Women's Health Pavilion location in the New York City area during an anti-abortion protest.[3] In 1990, Vaughan was arrested in Albany, New York, for trespassing on the grounds of a women's health clinic that provided abortion services. While serving ten days in jail, he stated that New York Governor Mario Cuomo was in ''serious risk of going to hell'' for his support of women's abortion rights.[1]
In the Catholic New Yorker, January 1987, Vaughan described himself as "one of the most conservative bishops in the Catholic Church, USA. (He was entrusted with the translation into English from the Latin of official Vatican documents. But he went on to say in his Catholic New Yorker newspaper article that he was enthralled by his attendance at an Epiphany celebration, January 6, 1987.