David Lewis was a Canadian labour lawyer and social democratic politician. He was national secretary of the Co-operative Commonwealth Federation (CCF) from 1936 to 1950 and one of the key architects of the New Democratic Party (NDP) in 1961. In 1962, he was elected as the Member of Parliament (MP), in the House of Commons of Canada, for the York South electoral district. While an MP, he was elected the NDP's national leader and served from 1971 until 1975. After his defeat in the 1974 federal election, he stepped down as leader and retired from politics. He spent his last years as a university professor at Carleton University, and as a travel correspondent for the Toronto Star. In retirement, he was named to the Order of Canada for his political service. After suffering from cancer for a long time, he died in Ottawa in 1981.

Francis Reginald Scott (1899–1985), commonly known as Frank Scott or F. R. Scott, was a lawyer, Canadian poet, intellectual, and constitutional scholar. He helped found the first Canadian social democratic party, the Co-operative Commonwealth Federation, and its successor, the New Democratic Party. He won Canada's top literary prize, the Governor General's Award, twice, once for poetry and once for non-fiction. He was married to artist Marian Dale Scott.