A 15-member, multi-party committee selected Colonel George Stanley and Liberal MP John Matheson’s design from among 3,541 submitted for consideration.
The chosen flag - a triband of red, white and red with an 11-pointed red maple leaf in the centre - was selected unanimously after six months of bitter, divisive debate.
Most English-speaking Canadians wanted to formally adopt the Red Ensign, a banner with a Union Jack in the corner, which had been used unofficially since 1870.
Canadian military veterans particularly wanted to maintain it as a sign of ties to the UK and other Commonwealth countries such as Australia and New Zealand.
Although, technically, Britain’s Union Flag – and not the Red Ensign - had remained the official flag despite the country being an independent confederation since 1867.
But residents in the French-speaking province of Quebec generally rejected all these “foreign” symbols and preferred either a neutral flag or one containing fleur-de-lys.
Liberal Prime Minister Lester B Pearson, who refused to hold a referendum on the issue, became convinced of the need for a distinctly Canadian banner in 1956.
During the Suez Crisis – after which he won the Nobel Peace Prize for brokering peace – Egyptians objected to Canadian peacekeeping forces on the grounds that their Red Ensign contained the same flag as one of the belligerents.
He also wanted to garner support among the Quebecoise, who were increasingly inclined to support independence for the Francophone region.
Many others had long felt Canada needed its own banner, especially as an increasing number of new immigrants did not have British ancestry or connections.
Indeed, Germans formed the biggest group of new arrivals between 1945 and 1965, despite their initial classification as “enemy aliens” after World War II.
The need for the country to have finally settled the issue became more pressing as it approached the 1967 celebration of the centenary of its foundation.
So Pearson, whose admirers persuaded Toronto’s airport to be renamed after him in 1984, launched a commission in June 1964.
Following four months of deliberation it agreed upon the design of the current flag and in December it was ratified by both of the Canadian Houses of Parliament.
Queen Elizabeth II, who is head of state in Canada, proclaimed the new standard as the country’s first official flag on January 28, 1965.
A U.S. News of the Day newsreel, which is contained in the British Pathé archive, showed the Maple Leaf banners being manufactured shortly beforehand in Toronto.
The commentator also explained bizarre flag situation of America’s northern neighbour to a no-doubt puzzled audience.
Yet despite lacking its own official standard for so many years, Canada’s Maple Leaf has become one of the most iconic and easily recognised flags in the world.
It ensured that the long beloved maple leaf symbol has become even more treasured by Canadians and features in nearly every sphere of life.
Canada, for example, is the only country in the world where the McDonald’s sign deviates – with a maple leaf instead of an apostrophe.