[3] McKenzie was ordained in the Episcopal Church as a deacon in June 2004 by Peter James Lee, Bishop of Virginia, during a service at Washington National Cathedral.
[2][3] On 6 January 2005, she was ordained as a priest by Charles L. Keyser, her cousin, the retired Bishop of the Armed Forces, during a service at St David's Episcopal Church in Washington, D.C.[2] From 2004 to 2007, she served as Assistant Rector at St David's Episcopal Church, Washington, D.C.[4] where she had served as seminarian from 2002-2004.
She was then Associate Rector of Christ Church, Alexandria, Virginia from July 2007 to March 2009, and Interim Associate Rector of the Church of the Good Shepherd, Burke, Virginia from June 2011 to December 2012.
[4][3] In August 2015, it was announced that McKenzie would join the Diocese of Liverpool in the Church of England as Archdeacon of Wigan and West Lancashire.
[7] Having returned to the United States, McKenzie has been Dean's advisor for new initiatives at Virginia Theological Seminary since 1 September 2021.