George Stack was born in Cork, Ireland on 9 May 1946. He attended school in Highgate, London, before entering seminaryat St. Edmund’s College, Ware in 1966. He was ordained deacon in 1971 and completed his seminary training 1972, being ordained priest on 21 May 1972 by Bishop Victor Guazzelli, an Auxiliary Bishop of the Archdiocese of Westminster.
Following ordination, Father Stack was appointed curate St Joseph’s, parish, Hanwell. Between 1974 and 1977, Father Stack pursued a Bachelor of Education degree at St Mary’s University College, Twickenham. He then became curate at St Paul’s, Wood Green, and in 1983 was appointed Parish Priest of Our Lady, Help of Christians in Kentish Town.
In 1990, he was appointed Vicar General for Clergy, a post based at Archbishop’s House in Victoria, London. He became Administrator of Westminster Cathedral in 1993, and was granted the title Monsignor.
In 2001, Monsignor Stack was consecrated an Auxiliary Bishop for the Archdiocese of Westminster, by Cardinal Cormac Murphy-O’Connor. In 2006, he was identified as holding responsibility for the pastoral care of deaneries in Hertfordshire and for Westminster’s Diocesan Department for Education and Formation.
On 19 April 2011, Bishop Stack was named as the 7th Archbishop of Cardiff. He was installed as Archbishop on 20 June 2011, and received the pallium in Rome from Pope Benedict XVI on 29 June 2011.