Bishop John was born on 19th December 1964 in Glasgow. He was educated at the Salesian College, Shrigley Park, Chesire; University of Glasgow 1984-1988 (LL.B); Gergorian University, Rome 1988-1995 (S.T.B., Ph.L).
Having studied at the Pontifical Scots College, Rome, he was ordained a priest on 9th July 1995 in St. Gregory's, Wynford by Cardinal Thomas Winning, Archbishop of Glasgow. He was an Assistant Priest in Christ the King, Kingspark from 1995-2000 and Chaplain at Holyrood High School, Glasgow from 1997 - 2000. He was a lecturer in Philosophy at Scotus College, Glasgow from 1995-2005. He was appointed as Chaplain to the University of Glasgow from 2000-2014 and Parish Priest of St. Patrick's, Anderston from 2013-2014. He was appointed as Vocations Director of the Archdiocese of Glasgow 2013-2014.
He was nominated as Bishop of Paisley, by Pope Francis, on 8th February 2014 and was ordained as the fifth Bishop of Paisley on 19th March 2014 by Archbishop Philip Tartaglia, the Archnishop of Glasgow and his predecesor in Paisley.