McGee studied for the priesthood at St. Patrick's College, Thurles (in County Tipperary, Ireland) between 1983 and 1989, where he received a Certificate in Philosophy (Distinction) validated by the Irish Governments National Council for Educational Awards and a Diploma in Theology (Distinction), accredited by Maynooth Pontifical University.

In 2011 he completed a Master of Arts degree in Christian Spirituality (Distinction) from Sarum College, Salisbury.

McGee was ordained in 1989 as a priest for the Diocese of Paisley by Bishop John Mone.

He was appointed by Pope Francis on 28 December 2015[3] and consecrated by Archbishop Leo Cushley on 18 February 2016 in St Columba's Cathedral, Oban.

[4] Bishops Joseph Toal of Motherwell, McGee's immediate predecessor, and John Keenan, bishop of his native diocese of Paisley, served as co-consecrators.