MacDonald competed at five successive IPC Athletics World Championships from 1994 to 2011. In 1994, he competed in 100m, 200m and 400m T35 events. In 1998, he won a bronze medal in Men's Shot Put F34 and competed in Men's 100m and 200m T35 events. There was controversy during the Men's Shot Put where MacDonald was forced to change his technique mid-competition due to an official's ignorance of the rules. In 2002, he won gold in the Men's Shot Put F34 in a world record (10.69m) and competed in Men's Discus F33-34. In 2006, he won gold in the Men's Shot Put F34 event and competed in the Men's Discus F33-34 event. In 2011, he finished 6th in Men's Shot Put F34.