Joseph Jean-Pierre Marc Garneau was born on February 23, 1949, in Quebec City, Quebec, Canada. He attended primary and secondary schools in Quebec City and Saint-Jean-sur-Richelieu. He received a Bachelor of Science degree in Engineering Physics from the Royal Military College of Canada in 1970, and in 1973 received a Doctorate in Electrical Engineering from the Imperial College of Science and Technology in London, England. From 1982 to 1983, he attended the Canadian Forces College in Toronto.

In 1974, Garneau began his career in the Royal Canadian Navy as a Naval combat systems engineer aboard HMCS Algonquin. He was promoted to Commander in 1982 while at Staff College and was transferred to Ottawa in 1983. In January 1986, he was promoted to Captain(N) and retired from the Navy in 1989.

Garneau was one of six first Canadian Astronauts and he became the first Canadian in outer space on October 5, 1984. In 1984, he was seconded to the new Canadian Astronaut Program (CAP), one of six chosen from over 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, 2000). He has logged over 677 hours in space.

Garneau was appointed an Officer of the Order of Canada in 1984 in recognition of his role as the first Canadian astronaut. He was promoted the rank of Companion within the order in 2003 for his extensive work with Canada’s space program.

Garneau was awarded the Key to the City of Ottawa from Marion Dewar the Mayor of Ottawa on 10 December 1984.

He was inducted into the International Space Hall of Fame in 1992.

In February 2001, he was appointed executive vice-president of the Canadian Space Agency, and became its president on November 22, 2001.

Garneau resigned as President of the Canadian Space Agency to run for the Liberal Party of Canada in the 2006 federal election in the riding of Vaudreuil—Soulanges, which was represented by Meili Faille of the Bloc Québécois. The Liberal Party’s support dropped off considerably in Quebec after the Sponsorship scandal and though considered a star candidate Garneau lost to Faille by over nine thousand votes.

In the 2006 Liberal Party leadership election Garneau announced his support for perceived front-runner Michael Ignatieff, who lost to Stéphane Dion on the final ballot. With the resignation of Liberal MP Jean Lapierre in 2007, Garneau expressed interest in being the party’s candidate in Lapierre’s former riding of Outremont. Dion instead appointed Jocelyn Coulon as the party’s candidate, who went on to be defeated by the New Democratic Party’s Thomas Mulcair in the by-election.

In May 2007, Garneau filed nomination papers to be the party’s candidate in Westmount—Ville-Marie, after former Liberal Party Deputy Leader Lucienne Robillard announced she would not be seeking re-election. However, a week after filing his nomination papers Dion announced that he had hand-picked a candidate for the riding. Garneau later withdrew his nomination papers and announced he no longer had an interest in politics. In October 2007, Garneau and Dion held a joint news conference where they announced that Garneau would be the Liberal Party candidate in Westmount—Ville-Marie. Robillard announced her resignation as Member of Parliament in January and a by-election was later scheduled for September 8, 2008. However, the by-election was cancelled during the campaign when Prime Minister Stephen Harper called a general election for October 14, 2008. Though some pundits predicted a close race between Garneau and NDP candidate Anne Lagacé-Dowson, Garneau went on to win the riding by over 9,000 votes.

Garneau was narrowly re-elected in the 2011 election where he beat New Democratic Party candidate Joanne Corbeil. He was Liberal House Leader and served as Liberal Foreign affairs Critic. He was a candidate for interim leadership of the Liberal Party, but was ultimately defeated by Bob Rae. Garneau announced later that year that he was considering a bid for the permanent leadership of the party. In the summer of 2012, he announced that he was looking for a “dream team” to run his leadership bid and that he would only run if he could find the right people.

On November 21, 2012, Garneau was named his party’s Natural Resources critic after David McGuinty resigned the post.

On November 28, 2012, Garneau announced his bid for the leadership of the Liberal Party, placing a heavy focus on the economy. While fellow leadership candidate Justin Trudeau was widely seen as the frontrunner in the race, Garneau was thought to be his main challenger among the candidates. With his entrance into the leadership race he resigned his post as Liberal House Leader, while remaining the party’s critic for Natural Resources.

On January 30, 2013, Garneau was replaced as Natural Resources critic by Ted Hsu. Garneau had been serving in the position on an interim basis.

On March 13, 2013 Garneau announced his withdrawal from the race, and threw his support to front-runner Justin Trudeau. On September 18, 2013, Garneau was named co-chair of the Liberal International Affairs Council of Advisors, providing advice on foreign and defence issues to Liberal Party of Canada leader Justin Trudeau.

In the 2015 elections held on October 19, 2015, Garneau was re-elected a Parliamentarian in the newly created riding of Notre-Dame-de-Grâce—Westmount. Two weeks later, on November 4, 2015, Garneau was appointed Transport Minister of Canada in the federal Cabinet headed by Justin Trudeau.

In May 2017, Garneau introduced an airline passenger bill of rights to standardize how passengers can be treated by airlines which operate any flights in and out of Canada. The legislation would create minimum compensation rates for overbooking, lost or damaged luggage, and bumping passengers off flights. It would also prohibit airlines from removing people from the flight if they have purchased a ticket and set the standard for tarmac delays and airline treatment of passengers when flights are delayed or cancelled over events in the airline’s control, or because of weather conditions.

In March 2019, after days of initial refusal to take actions following the crash of Ethiopian Airlines Flight 302, Garneau finally agreed to ground and prohibit all Boeing 737 Max aircraft from flying in Canadian airspace. This stood in contrast to the ministry’s previous stance, where he insisted the plane was safe to fly, thus making Canada one of the only two nations still flying a substantial number of Boeing 737 Max planes at the time. Garneau even went so far as saying he would board 737 MAX 8 “without hesitation”, as an apparent show of support for the Boeing Company.