It was contested between the defending champion Toronto Maple Leafs and the Detroit Red Wings for the second straight year.
The Maple Leafs overcame a 3-2 series deficit to defeat the Red Wings in seven games for their third-straight championship.
In game six of the Final, he took a Gordie Howe slapshot on his ankle and had to leave play.
MacMillan won the Cup with the 1963 Toronto Maple Leafs in a five-game decision over Detroit and then lost the 1964 Cup Final to the Leafs as a member of the Red Wings.
The 1964 Stanley Cup was presented to Maple Leafs captain George Armstrong by NHL President Clarence Campbell following the Maple Leafs 4–0 win over the Red Wings in game seven.