He was born in Quebec City. He was educated in Quebec and in London, England. He gained a degree in engineering physics at the Royal Military College of Canada in 1970 and a doctorate from Imperial College, London in 1973.
He joined the Canadian Navy in 1974 to work as an engineer. He first served as a systems engineer aboard the HMCS Algonquin until 1976. From there he went as an instructor to the Canadian Forces Fleet School in Halifax. He worked with the Naval Engineering Unit and in 1982 he was promoted to Commander.
In 1984 he was seconded to the new Canadian Astronaut Program (CAP), one of six chosen from 4,000 applicants. He flew on the shuttle Challenger, STS-41-G from October 5 to 13, 1984 as payload specialist. He was promoted to Captain in 1986 and left the Navy in 1989 to become Deputy Director of the CAP. In 1992-93 he underwent further training to become a mission specialist. He worked as CAPCOM for a number of shuttle flights and was on two further flights himself - STS-77 (May 19 to 29, 1996) and STS-97 (to the ISS, November 30 to December 11, 200). He has logged almost 678 hours in space. In 2001 he was appointed Executive Vice President of the Canadian Space Agency.
In August 2003, Capt. Garneau was made a Companion of the Order of Canada, Canada's highest honour. He is also honoured with a high school name after him in Toronto [1].