He holds the degrees of Ph.L. and South.T.L. from the Pontifical Gregorian University in Rome and is also a graduate of the University of Aberdeen where he received an Master of Education degree as well as the University of Glasgow where he earned an Master of Arts
Honours) degree in Classics. At the request of his bishop he attended the University of Glasgow to prepare for a teaching post in Blairs College, then the national minor seminary for Scotland. After graduating in 1963 he trained at Jordanhill College of Education and joined the Blairs College staff in 1964, where he remained until 1986.
He also served in a variety of pastoral appointments before becoming bishop: Priest in Charge of Saint Mary's Parish, Blairs.
Parish Priest of Inverurie and also as chaplain to various schools. He served from 1986 to 2002 on the Education Committees of now defunct Grampian Region and later of Aberdeenshire.
When Bishop Mario Conti became Archbishop of Glasgow on 22 February 2002, Peter Moran was elected to the caretaker post of Diocesan Administrator of Aberdeen before being appointed bishop by Pope John Paul II on 13 October 2003. He was consecrated as on 1 December 2003 by Archbishop Mario Joseph Conti in the Cathedral of Saint Mary of the Assumption, Aberdeen.
His personal motto is, in Latin, Gaudium et spes - "Joy and Hope" - which is also the title of Vatican II"s Pastoral Constitution on the Church in the Modern World.
He is a Life Member of the Educational Institute of Scotland (Executive Information System ) and chaplain to the French-speaking Catholic community of (mainly oil-related) expatriates in Aberdeen.