MacKenzie moved from his native Scotland to the United States with his family as a teenager, settling in Midlothian, Virginia.
He attended Clover Hill High School and played college soccer at Old Dominion University from 2003 to 2006, where he finished his four seasons as team captain, having played eighty-one games and scored fourteen goals.
During his college years MacKenzie also played with Richmond Kickers Future and the Williamsburg Legacy in the USL Premier Development League.
[1] Prior to moving to the United States, he scored a record 67 goals in the Scottish Youth League, and was a member of the youth academies at storied Scottish league clubs St Johnstone and Dundee United.
[2] He made his professional debut, and scored his first professional goal, on 24 May 2007, coming on as a substitute in a 2–2 with the Cincinnati Kings[3] On 16 April 2008 MacKenzie signed with the Carolina RailHawks of the USL First Division, but he ultimately played just one game for the team, and moved to the Richmond Kickers of the USL Second Division for the 2009 season.