Bishop Dunn was born on January 8, 1955, in St. John’s, Newfoundland. He obtained a Bachelor of Arts from King’s College as well as a Master of Divinity from the University of Western Ontario. He was ordained to the priesthood on August 28, 1980, for the Diocese of Grand Falls where he served as pastor and in a number of other responsibilities, including Vice-Chancellor and Chancellor. In 1991, he obtained a Doctorate in Canon Law from Saint Paul University (Ottawa) and soon after became a lecturer in the Diploma Program for Theology and Ministry at the Atlantic School of Theology, Halifax, Nova Scotia (1992-1999). Beginning in 2002, he served on the faculty at St. Peter’s Seminary in London, Ontario and became Dean of Studies at the seminary until 2008. During this same time period, Bishop Dunn also served as a Lecturer with the Faculty of Canon Law at Saint Paul University (2003-2004 & 2007). He was appointed Auxiliary Bishop of Sault Ste-Marie on July 16, 2008, and consecrated on October 9, 2008. He was appointed Bishop of Antigonish on November 21, 2009, and installed on January 25, 2010.
As a member of the Canadian Conference of Catholic Bishops (CCCB), he served as a member of the former Episcopal Commission for Catechesis (English Sector) and the Standing Committee on Relations with Catholic Movements and Associations (2009-2010). He currently serves as a member for the Commission for Liturgy and Sacraments (English Sector), the Episcopal Ad Hoc Committee for the elaboration of the new English-language Ratio Nationalis (Program for Priestly Formation), the Liaison Bishop of the International Committee on English in the Liturgy (ICEL), and as co-Chair of the Anglican/Roman Catholic Dialogue.
According to the CCCB 2019 Directory, the Archdiocese of Halifax-Yarmouth has 88 parishes and missions, with a Catholic population of 182,430 served by 69 diocesan priests, 12 priests who are members of institutes of consecrated life, 43 permanent deacons, as well as 102 Sisters who are members of religious institutes, in addition to six lay pastoral workers.