[1] Knowles was widely regarded and respected as the foremost expert on parliamentary procedure in Canada, and served as the CCF and NDP House Leader for decades.

He was also a leading advocate of social justice,[1] and was largely responsible for persuading the governments to increase Old Age Security benefits and for the introduction of the Canada Pension Plan,[1] as well as other features of the welfare state.

He was first elected to the House of Commons in a 1942 by-election in Winnipeg North Centre that was held on the death of former CCF leader J. S. Woodsworth.

The year after, in 1958, Knowles was narrowly defeated by John MacLean, his Tory challenger in 1957, in an election that almost wiped out the CCF.

He retired from politics in 1984, but was given the unprecedented distinction of being made an honorary table officer of the House of Commons by Prime Minister Pierre Trudeau.

[1] This allowed him to spend his retirement viewing parliamentary debates from the floor of the House, and he was often seen to do so until further strokes left him bedridden.

[4] From 1970 to 1990, he was the chancellor of Brandon University, and today has the school's student union building named after himself and Tommy Douglas.