He returned to Rome in 1976 to earn a licentiate in canon law and a doctorate in moral theology and to prepare for a diplomat's career at the Pontifical Ecclesiastical Academy.
[citation needed] He entered the diplomatic service of the Holy See on 25 March 1980, working at nunciatures in South Africa, Senegal, India, Yugoslavia, Cuba, and Egypt.
[2] He received episcopal ordination on 12 November 2000 at St Mary of the Rosary Church in Nenagh from Cardinal Francis Arinze, Prefect of the Congregation for Divine Worship and the Discipline of the Sacraments, with Bishops John Kirby and William Walsh as co-consecrators.
[4][6] In December 2003, as Courtney was returning to Bujumbura from a funeral,[6] gunmen fired at his car near Minago, 30 miles (48 km) south of the capital.
He suffered gunshot wounds to the head, shoulder and leg and died from hemorrhaging during surgery at The Prince Louis Rwagasore Hospital in Bujumbura.