Born in Vestfold, Manitoba, a son of Icelandic immigrants Guðmundur and Jonina Stefansson, he served in the Canadian army during World War II.
He worked in the Department of Plant Science for the University of Manitoba as a professor and researcher.
He worked with Dr. Keith Downey to develop a variety of rapeseed that could be used as an edible oil.
This is known as canola and is one of Canada's top edible oil and one of the largest oilseed crops in the world.
In 1998 he was awarded the Order of the Buffalo Hunt, one of Manitoba's highest honours.