 A St George junior from the Brighton Seagulls club, Mackay was graded by the Dragons in 1987 and then played 117 games with club over eight seasons till 1994 scoring 22 tries.Playing all positions in the backline bar halfback, he was most remembered for his lock position in his peak.Mackay debuted for the New South Wales Blues as a reserve in game II of the 1989 State of Origin series.