Father Rooney studied at Chesters and Scotus Colleges in Glasgow where he took his Diplomas in Philosophy and Theology from the Pontifical University of Maynooth. He was ordained priest on 26 June 1998 by Bishop Joseph Devine in St Gerard's, Bellshill. He was the first ordination in that Parish .
After his ordination, he was appointed as a curate in St Columbkille's, Rutherglen. He then served in Sacred Heart, Bellshill and Our Lady of Lourdes, East Kilbride before becoming the Parish Priest of Our Lady and St John's, Blackwood and St Mary's, Larkhall As these were merged into one parish, he became Parish Priest of the new Parish of Our Lady of Fatima.
In February 2020, He was appointed Parish Priest of St Ignatius' Wishaw.
With the retirement of Father Kelly; Father Rooney also became Parish priest of St Brigid's, Newmains. With the retirement of Father Magill of St Athanasius, Carluke, Fr. Rooney was again on the move being made Parish Priest of St Athanasius, Carluke and St Brigid's, Newmains. Still in charge of two parishes.