After attending St. Charles College in Sudbury, where he was taught by the Basilian Fathers, he obtained his Baccalaureate in Mathematics in 1973 from Queens University, Kingston, and then a Master of Mathematics in 1974 from the University of Toronto.
In 1975, he entered the Basilian novitiate in Rochester and took his first vows on August 15 of the following year. He then undertook studies at the Faculty of Theology of the University of St. Michael’s College, and at the Basilian House of Formation in Toronto. He obtained his Master of Divinity degree in 1979.
He was ordained to the priesthood on May 3, 1980.
In 1983, he completed a Licence in Theology at the Pontifical Gregorian University in Rome, and in 1989, he was awarded a Doctorate in Moral Theology from that same university.
From 1986 to 1990, he was an Assistant Professor of Theology at St. Joseph’s College in Edmonton, and from 1990 to 1997, he was Professor of Theology at the University of St. Michael’s College in Toronto. Chosen as a General Councillor of the Basilians in 1993, he became General Superior of the Basilians in 1997, a post he held until 2002.
He was ordained Bishop of the Diocese of London on August 15, 2002.
He was granted an Honorary Doctorate of Divinity on Saturday, November 16, 2002, from the University of St. Michael's College.
Named the 10th Bishop of London on April 27, 2002, he was ordained to the episcopate on August 15, 2002 at St. Peter’s Cathedral Basilica in London, Ontario.
Bishop Fabbro was a member of the Theology Committee of the Canadian Religious Conference (National), and served on the Administrative Council of the Canadian Religious Conference (Ontario).
He has also served as a member for several CCCB Commissions and Committees, the Episcopal Commission for Liturgy, the Catholic Organization for Life and Family (COLF), and continues to be an active member on the Canadian Council of Churches Governing Board.
Bishop Fabbro is presently active as a member on the ACBO Executive Committee as Vice President, the Education Commission, and is also on the Board of Directors for the Institute for Catholic Education.