After his first year, he was ordained a [[priest]] on [[July 31]], 1993, and was assigned as rector of St Michael's Church in Old Forge, Pennsylvania, which allowed him to continue his studies and reunite his family. Fr David graduated ''cum laude'' from St Tikhon's in 1997, before starting further studies at the University of Scranton in 1999 with Bachelors of Arts majoring in Theology and in Philosophy and graduating ''magna cum laude'' in 2003 (with awards for Academic Excellence and Excellence in Philosophy, and giving Presidential Honors in 2000, 2001 and 2003 from the University President), and graduating from a Master of Arts in Theology degree (also from the University of Scranton). He continued to serve at St Michael's until January 2006, when he was transferred to the pastorate of Holy Trinity Church in Pottstown, Pennsylvania, and was then transferred from there to be Acting Rector of St Nicholas Orthodox Church, Bethlehem, PA. He also served as [[dean]] of the Philadelphia Deanery, as Treasurer of St Tikhon's Alumni Association, Secretary of the NEPA Chapter of Alpha Sigma Nu Alumni, Secretary of the Clergy Brotherhood of NEPA, Staff of ''Your Diocese Alive in Christ'' magazine, auditor of the [[OCA]] and the Diocese of Eastern Pennsylvania, and on the Bishop's Task Force on Missions and Evangelism for the Diocese of Eastern Pennsylvania. He was elevated to [[Archpriest]] in 2002 and awarded the [[palitsa]] in 2006.[http://holytrinity-oca.org/wp-content/uploads/2011/05/HTOC-Trisagion-2008-10.pdf]

In 1997Between 2003-04, he received Fr. David served as a Master graduate assistant in the Theology Department of Divinity degree the University of Scranton, before serving from 2005-11 as Adjunct Lecturer in Philosophy, Doctrine, Church History, Comparative Theology and Modern Belief at [[St. Tikhon's Orthodox Theological Seminary|St. Tikhon’s Seminary]] in South Canaan, Pennsylvania. In 2003, he graduated and from March 2009 as Adjunct Lecturer in theology and philosophy at the Melrose Park Campus of Alvernia University of Scranton with Bachelors degrees in Theology and Philosophy. In 2005Philadelphia, he also received his Master of Arts degree in Theology from the University of ScrantonPennsylvania.

Between 2003-04Tragically, on [[August 8]], 2007, Fr. David served as a graduate assistant 's wife, Matushka Karen, fell asleep in the Theology Department of the University of Scranton, before serving from 2005 as Adjunct Lecturer in Philosophy, Doctrine, Church History, Comparative Theology and Modern Belief at Lord.<ref>[[Sthttp://doepa. Tikhon's Orthodox Theological Seminary|Storg/news_070809_1. Tikhon’s Seminaryhtml]], and from March 2009 as adjunct lecturer in theology and philosophy at the Melrose Park Campus of Alvernia University in Philadelphia, Pennsylvania.In Memoriam: Matushka Karen Mahaffey</ref>

In subsequent years, Fr David became nominated for a series of sees - to the Diocese of Western Pennsylvania in November 2008, to the Diocese of New York and New Jersey in August 2009, to the Diocese of the Midwest in October 2010. On [[August 8September 15]], 20072012, Frhe was nominated by the delegates to the Assembly of the [[Diocese of Alaska (OCA)|Diocese of Alaska]] as the candidate for election as Bishop of Sitka and Alaska by the [[Holy Synod]]. David He was tonsured a [[riassaphore]] on September 23 by Abp [[Tikhon (Mollard) of Washington|Tikhon]] at St Tikhon's wife, Matushka Karen, fell asleep in the LordSeminary.<ref>[http://doepa.org/news_070809_1news_120924_6.html] In Memoriam: Matushka Karen Mahaffey</ref> In 2009, he was assigned rector of St. Nicholas Church in Bethlehem, Pennsylvania.

On [[September 15]] 2012 he was nominated by the delegates to the Assembly of the [[Diocese of Alaska (OCA)|Diocese of Alaska]] as the candidate for election as Bishop of Sitka and Alaska by the [[Holy Synod]]. On October 9-11, 2012 the Holy Synod of OCA accepted Archbishop [[Benjamin (Peterson) of San Francisco|Benjamin’s]] presentation of Hieromonk David (Mahaffey) as the nominee for the Episcopal See of Alaska<ref>[http://oca.org/news/headline-news/holy-synod-of-bishops-concludes-fall-session Holy Synod of Bishops concludes fall session]</ref>. On Friday, February 21, 2014, Hieromonk Archimandrite David was consecrated Bishop of Alaska during a Hierarchical Liturgy by [[Metropolitan]] [[Tikhon (Mollard) of Washington|Tikhon of Moscow]], Archbishop [[Benjamin (Peterson) of San Francisco|Benjamin of San Francisco]], Bishop [[Michael (Dahulich) of New York|Michael of New York]], Bishop [[Irineu (Duvlea) of Dearborn Heights|Irineu of Dearborn Heights]], and Bishop [[Irénée (Rochon) of Quebec City|Irénée of Quebec City]] at St Innocent Cathedral in Anchorage, Alaska. Co-serving the bishops were [[Chancery office of the Orthodox Church in America|Chancellor for the Orthodox Church in America]] [[Archpriest]] [[John A. Jillions]], Archpriest Victor Nick ([[Chancellor]] of the Diocese of Alaska), and 40 other priests from around the diocese. A banquet was held in his honor that evening at the University of Alaska’s Lucy Cuddy Center in Anchorage<ref>[http://oca.org/news/headline-news/banquet-honoring-bishop-david-held-at-university Banquet honoring Bishop David held at University]</ref>.