Born 24th June 1941 to Thomas and Margaret Clifford, Bellurgan in the Parish of Lordship and Ballymascanlon. Educated at Bellurgan National School, Bush Post-Primary School, St. Mary’s College, Dundalk, St. Patrick’s College, Armagh and St Patrick’s College, Maynooth. Degree in Celtic Studies (1963) and Bachelor of Divinity (1966).

Ordained priest 18th June 1967 he did post-graduate studies at St. Patrick’s College Maynooth, (Licentiate in Divinity; S.T.L.). Did further post-graduate studies at the Lumen Vitae International Catechetical Center, Brussels, (Dip. En Sc. Rel. 1969). In 1969 he was appointed Diocesan Adviser for Religious Education and served in that post for ten years. During that time he published catechetical material for teachers and parents.

In 1979 he was appointed curate in Portadown and Diocesan Adviser for Ecumenism. He worked closely with Canon William Arlow, who held a similar post in the Church of Ireland. In 1980 he was appointed curate in the parish of Kilmore, Armagh and continued his work in ecumenism. In 1984 he was appointed first full-time Executive Secretary of the Irish Bishops’ Conference and held that post until 1991 when he was appointed Auxiliary Bishop to the Archbishop of Armagh and Titular Bishop of Geron.

His Episcopal Motto ‘Ut Unum Sint’, (that they may be one), expresses the hoped-for reconciliation of the two principal Christian traditions in Ireland. He is a member of the Bishops’ Commission for Ecumenism, the Advisory Committee on Ecumenism and the Inter-Church Standing Committee on Mixed Marriages. For many years he has been a member of the Irish Inter-Church Committee (Ballymascanlon Conference). He is also a member of the Episcopal Commission for Missions.

The chequered pattern of the shield serves to remind us of the two principal Christian traditions found in Ireland. The hoped-for reconciliation of those traditions finds expression in Bishop Clifford's motto, Ut Unum Sint (That they may be One).

The scallop shell motif is abstracted from the old shield of arms of the Mulholland family, the maternal forebears of the Bishop; this family is traditionally reputed to have been the guardians of the bell of St Patrick, a theme commemorated by the symbol of a bell on the Bishop's personal shield.