Lemieux writes that his childhood neighbourhood of the Boyle Street area was "an Irish-French-Ukrainian ghetto where the main challenge was to avoid associations that could lead to reform school." As a child he had moved there with his family from Lac la Biche.
This self-proclaimed "poor boy from the sticks" was raised by his oldest sister. Chemistry was his favourite subject in school. His University studies were in chemistry at the University of Alberta and McGill University in Montreal. He and a colleague at the National Research Council in Saskatoon became the first scientists to synthesize sucrose, ordinary sugar. He returned to Edmonton in 1961 to become a professor and a chairman in Chemistry at the University of Alberta. "The Gunning/Lemieux Chemistry Centre" was unveiled at the University of Alberta in November 2001.