Admiral Arthur Gerard McDonald, is a Royal Canadian Navy admiral who served as Chief of the Defence Staff of the Canadian Forces from January 14, 2021, until February 24, 2021, when he voluntarily stepped aside due to an investigation by the Canadian Forces National Investigation Service. On November 25, 2021, McDonald was formally relieved of his command, and replaced permanently by General Wayne Eyre who had held the post during the interim.

The chief of the Defence Staff is the professional head of the Canadian Armed Forces. As the senior military position, the chief of the Defence Staff advises the Cabinet, particularly the minister of national defence and the prime minister. The role is a Crown-in-Council appointment made by the viceroy on the advice of the prime minister.