The Montreal MP made the announcement at a news conference in his home riding.
”Whether it was in the Canadian Navy, as an astronaut or as president of the Canadian Space Agency, I have spent my life serving my country,” Garneau said. ”And I am extremely proud of who I am and my contribution to my the country. I believe in commitment and in excellence in everything I do.”
Garneau joins a crowded field that includes fellow Montreal MP — and leadership favourite —Justin Trudeau.
The 63-year-old Garneau was first elected to the House of Commons in 2008 and was re-elected in 2011.
The Quebec City native became the first Canadian in space when he flew aboard the Challenger shuttle in 1984.
Garneau served as president of the Canadian Space Agency from 2001 to 2005 before jumping into politics.