Constitutionally, command-in-chief is vested in the Canadian sovereign, presently Queen Elizabeth II but the actual title of Commander in Chief of the Canadian Armed Forces (domestic title) and Commander in Chief of Canada (international title) is conferred upon the Governor General.

In 1904, the exercise of the duties of the commander-in-chief were delegated to the Governor General of Canada.  Following this, in 1905, the letters patent constituting the Office of the Governor General were amended to read the "Letters Patent constituting the Office of the Governor General and Commander-in-Chief."

The letters patent issued in 1947 by King George VI referred to the Office of Governor General and Commander-in-Chief in and over Canada.