His episcopal consecration took place on 3 May 2017. Harris was born in Brisbane on 29 October 1962 to Shirley and Jim Harris. He has a sister named Jennifer. He was educated at Nundah Convent, Virginia State School and St Joseph’s Nudgee College before working for five years as a public relations agent for the Bank of New South Wales.
He attained a Bachelor of Theology in 1991; and was subsequently ordained a deacon of the Archdiocese of Brisbane on 5 June 1992, receiving priestly ordination at the age of thirty on 18 November 1992. Over the almost twenty-five years of his priesthood, he was first an Assistant Pastor in Grovely parish, and then in Caboolture parish; before being appointed parish priest of Corinda-Graceville in 1996, a position in which he served until he was transferred to Surfers Paradise in 2010, where he remained until he became bishop.His hobbies include Irish music (especially ballads), the beach (having lived at Surfers Paradise for seven years), and sports of all kinds.