Mackay began playing at the junior level Deportivo La Coruna, coming to play on occasion with the first team and frequently called for training with the squad. In this first year pro, was loaned to AD Ceuta and the University of Oviedo (both clubs 2 ª B). In 2007 he signed a contract with Neighborhood UD, the 2 nd Division B. Notably, at the age of 16, when he was goalkeeper of Deportivo Juvenil B, was called up by Scotland under-17.
In 2008 Mackay returned to Galicia, particularly the City of Santiago, which that year began to sink into a severe financial crisis. The following summer, he went to the SD Ponferradina, berciano club with that in the 2009/2010 season won promotion to the Second Division thanks to a decisive stop him in the shootout.
Today in the 2010/2011 season, remains the goalkeeper at the SD Ponferradina, curdled good performances and trying to help wherever possible to keep the team in the category.