Prior to February 1, 2006, he served the diocese as diocesan theologian and pastor of a clustered parish known as the Manoa-Punahou Catholic Community.
After completing his seminary studies in the American College of Louvain (Leuven), he was ordained to the presbyterate for the diocese of Honolulu at Saint John Vianney Church in Kailua on October 18, 1985, where he served as a parochial vicar.
From 1987 until 1990 he served as an associate director for adult religious education/catechesis for the Diocese of Honolulu, with an office at Saint Stephen Diocesan Center.
Bishop Clarence Silva appointed Alexander to the office of vicar general for the Diocese of Honolulu effective February 1, 2006.
Alexander resigned as the Homeless Coordinator for the Hawaii Governor's Office in January 2012 due to an affair with a woman while he was an ordained Catholic Priest.