Bishop Treanor was born on 25 December 1950 in Siverstream, Ireland. He studied art and philosophy, then turned towards theology and completed his licentiate. On 13 June 1976, he was ordained a priest and on 29 June 2008 was consecrated a Bishop, for the diocese of Down and Connor. From 1993 to 2008 he was General Secretary of the Commission of the Bishops’ Conferences of the European Union (COMECE).
Mgr. Treanor is Delegate of the Irish Bishops’ Conference to COMECE since 2009.