Since being drafted in 2006 with the 46th Pick, Mackay has played 220 games for the Adelaide Crows whilst kicking 60 goals. An explosive and agile wingman, Mackay is best regarded for his ability to break the game open with his run and carry. Mackay is only the 16th Crow to play more than 200 senior games for the club.
Since his first year at the Crows where he was awarded the Mark Bickely Award for the best first year player, Mackay has continued to excel at the club. Known for his professionalism, Mackay was appropriately awarded the Dr Brian Sando OAM Trophy in 2016, an award that recognizes the elite standards of an individual in their preparation as an AFL footballer. Furthermore, Mackay was awarded life membership of the Adelaide Crows in 2016.
Mackay averaged 16.9 disposals and 3.5 tackles in the 2017 season from 22 games. The Adelaide Crows finished minor premiers in 2017 however unfortunately failed to win the AFL Grand Final. 2018 saw a new challenge for Mackay who played 17 games and averaged 16.6 disposals a game across a variety of positions. In 2019 Mackay averaged 17.2 disposals, he will look to continue with his consistency in season 2020.