Hadfield attended White Oaks Secondary School in Oakville, Ontario until his senior year and then graduated as an Ontario Scholar from Milton District High School in 1977. As a member of the Royal Canadian Air Cadets, he earned a glider pilot scholarship at age 15 and a powered pilot scholarship at age 16. After graduating from high school in 1978, he joined the Canadian Armed Forces and spent two years at Royal Roads Military College followed by two years at the Royal Military College, where he received a bachelor’s degree in mechanical engineering in 1982. He also conducted his post-graduate research at the University of Waterloo in 1982. Before graduating, he also underwent basic flight training at CFB Portage la Prairie. In 1983, he took honours as the top graduate from Basic Jet Training at CFB Moose Jaw, and then went on to train as a tactical fighter pilot with 410 Tactical Fighter Operational Training Squadron at CFB Cold Lake, flying the Canadair CF-116 Freedom Fighter and the McDonnell Douglas CF-18 Hornet. After completing his fighter training, Hadfield flew CF-18 Hornets with 425 Tactical Fighter Squadron, flying intercept missions for NORAD. He was the first CF-18 pilot to intercept a Soviet Tupolev Tu 95 long-range bomber in the Canadian Arctic.

In May 1992, Hadfield graduated with a master’s degree in aviation systems from the University of Tennessee Space Institute, where his thesis concerned high-angle attack aerodynamics of the F/A-18 Hornet fighter jet. In total, Hadfield has flown over 70 different types of aircraft.

Hadfield was selected to become one of four new Canadian astronauts from a field of 5,330 applicants in June 1992. Three of those four (Dafydd Williams, Julie Payette and Hadfield) have flown in space. The fourth candidate, Michael McKay, resigned as an astronaut in 1995. Hadfield was assigned by the Canadian Space Agency (CSA) to the NASA Johnson Space Center in Houston, Texas in August, where he addressed technical and safety issues for Shuttle Operations Development, contributed to the development of the glass shuttle cockpit, and supported shuttle launches at the Kennedy Space Center, in Florida. In addition, Hadfield was NASA’s Chief CAPCOM, the voice of mission control to astronauts in orbit, for 25 Space Shuttle missions. From 1996 to 2000, he represented CSA astronauts and coordinated their activities as the Chief Astronaut for the CSA.

Hadfield served as Mission Specialist 1 on STS-74 in November 1995. It was NASA’s second space shuttle mission to rendezvous and dock with the Russian Space Station Mir. During the flight, the crew of Space Shuttle Atlantis attached a five-tonne docking module to Mir and transferred over 1,000 kg of food, water, and scientific supplies to the cosmonauts. Hadfield flew as the first Canadian to operate the Canadarm in orbit, and the only Canadian ever to board Mir.

Hadfield is the recipient of numerous awards and special honours. These include appointment to the Order of Ontario in 1996 and the Officer of the Order of Canada in 2014, receipt of the Vanier Award in 2001, NASA Exceptional Service Medal in 2002, the Queen’s Golden Jubilee Medal in 2002, and the Queen’s Diamond Jubilee Medal in 2012. He is also the only Canadian to have received both a military and civilian Meritorious Service Cross, the military medal in 2001 and the civilian one in 2013. In 1988, Hadfield was granted the Liethen-Tittle Award (top pilot graduate of the USAF Test Pilot School) and was named US Navy Test Pilot of the Year in 1991. He was inducted into Canada’s Aviation Hall of Fame in 2005 and commemorated on Royal Canadian Mint silver and gold coins for his spacewalk to install Canadarm2 on the International Space Station in 2001. Further, the Royal Military College granted Hadfield an honorary Doctorate of Engineering in 1996 and he was presented with an honorary Doctorate of Laws from Trent University three years later. In 2013, Hadfield was presented with an Honorary Diploma from Nova Scotia Community College. Upon his taking command of the International Space Station, Elizabeth II, Queen of Canada, sent Hadfield a personal message of congratulations, stating “I am pleased to transmit my personal best wishes, and those of all Canadians, to Colonel Christopher Hadfield as he takes command of the International Space Station…”

In Sarnia, the city airport was renamed to Sarnia Chris Hadfield Airport in 1997 and there are two public schools named after him – one in Milton, Ontario and the other in Bradford, Ontario. A NASA Marshall Space Flight Center-run rocket factory at Michoud Assembly Facility in New Orleans, where he briefly worked, and an asteroid 14143 Hadfield are also named after him.

In April 2001, Hadfield served as Mission Specialist 1 on STS-100, International Space Station (ISS) assembly Flight 6A. The crew of Space Shuttle Endeavour delivered and installed Canadarm2, the new Canadian-built robotic arm, as well as the Italian-made resupply module Raffaello. During the 11-day flight, Hadfield performed two spacewalks, which made him the first Canadian to ever leave a spacecraft and float freely in space. During his first spacewalk Hadfield experienced severe eye irritation due to the anti-fog solution used to polish his spacesuit visor, temporarily blinding him and forcing him to vent oxygen into space. In total, Hadfield spent 14 hours, 50 minutes outside, travelling 10 times around the world during his spacewalk.

Hadfield is a civilian CSA astronaut, having retired as a colonel from the Canadian Armed Forces in 2003 after 25 years of military service. He was Chief of Robotics for the NASA Astronaut Office at the Johnson Space Center in Houston, Texas from 2003–2006 and was Chief of International Space Station Operations from 2006–2008. In 2008 and 2009, he trained as a back-up to Robert Thirsk on the Expedition 21 mission. In May 2010, Hadfield served as the commander of the NEEMO 14 mission aboard the Aquarius underwater laboratory, living and working underwater for fourteen days. NASA announced in 2010 that Hadfield would become the first Canadian commander of the International Space Station, leading Expedition 35 after its launch on December 19, 2012. His craft docked with the station on December 21. He remained on the station for five months, transferring control to Pavel Vinogradov and departing on May 13, 2013.

In 2005, 820 Milton Blue Thunder Squadron was renamed 820 Chris Hadfield Squadron in honour of Hadfield, who was a cadet there from 1971 to 1978. The Town of Milton also named a municipal park and street after Hadfield.

Hadfield is enthusiastic about the prospects for a manned mission to Mars, and when asked in 2011 if he would consider being the first to visit even if the journey to Mars were one-way, he said “I would be honoured to be given the opportunity.”

On December 19, 2012, Hadfield launched in the Soyuz TMA-07M flight for a long duration stay on board the ISS as part of Expedition 35. He arrived at the station two days later, as scheduled, and became the first Canadian to command the ISS when the crew of Expedition 34 departed in March 2013. On May 12, 2013 he turned over command of the ISS, and returned home aboard the Soyuz spacecraft on 13 May. He received significant media exposure during his time on the ISS, and ended his time on the station by paying tribute to David Bowie with a rendition of “Space Oddity”.

During his free time on Expedition 35, Hadfield recorded music for an album, using the Larrivée Parlor guitar previously brought to the ISS. The first song recorded in space, Jewel in the Night, was released via YouTube on Christmas Eve 2012.

Hadfield is of northern English and southern Scottish descent. He is a devoted fan of the Toronto Maple Leafs and wore a Leafs jersey under his spacesuit during his Soyuz TMA-07M reentry in May 2013. After the 2012 NHL Lockout ended, Hadfield tweeted a photo of himself holding a Maple Leafs logo, and stated he was “ready to cheer [his team] on from orbit”. He sang the Canadian National Anthem during the Toronto Maple Leafs and Montreal Canadiens game on January 18, 2014 at the Air Canada Centre in Toronto.

In June 2013, one month after completing his third trip to space, Hadfield announced his retirement from the Canadian Space Agency, effective July 3, 2013. Hadfield stated that after living primarily in the United States since the 1980s for his career, he would be moving back to Canada, “making good on a promise I made my wife nearly 30 years ago—that yes, eventually, we would be moving back to Canada.” He noted that he plans to pursue private interests outside government there.

Hadfield has a social media presence, with over 2,400,000 Twitter followers as of August 2019. He created one of the top Reddit AMA threads of all time on February 17, 2013. He is also on Facebook, Tumblr, and YouTube. His exchanges with William Shatner and other Star Trek actors have received media coverage. Hadfield has been described by Forbes as “perhaps the most social media savvy astronaut ever to leave Earth”.

His collaboration with Ed Robertson of the Barenaked Ladies and the Wexford Gleeks, Is Somebody Singing?—sometimes shortened I.S.S.—was aired on the CBC Radio program Q and released by CBC Music online on February 8, 2013. Hadfield sang Is Somebody Singing along with singers across Canada for the national Music Monday program. Hadfield has been credited musically on his brother Dave Hadfield’s albums. He also has performed with his brother the “Canada Song”, which was released on YouTube on Canada Day, 2014.

On May 12, 2013, after handing over command of the ISS, but before returning home, Hadfield released a music video recorded on the ISS of a modified rendition of “Space Oddity” by David Bowie. As of January 2020, the video has over 45 million views on YouTube. The performance was the subject of a piece by Glenn Fleishman in The Economist on May 22, 2013, analysing the legal implications of publicly performing a copyrighted work of music while in earth orbit.

In October 2013 Hadfield was interviewed by Maclean’s magazine and appeared on its cover wearing face make-up to “replicate Bowie’s famed image from the cover of his Aladdin Sane album.” Hadfield wrote an article for the December 2013 edition of Wired magazine in which he reflects on his time spent on the International Space Station.

On October 8, 2013 the University of Waterloo announced that Hadfield will join the university as a professor for a three-year term beginning in the Fall of 2014. Hadfield’s work is expected to involve instructing and advising roles in aviation programs offered by the Faculty of Environment and Faculty of Science, as well as assisting in ongoing research regarding the health of astronauts with the Faculty of Applied Health Sciences.

Hadfield’s 2013 autobiography, An Astronaut’s Guide to Life on Earth: What Going to Space Taught Me About Ingenuity, Determination, and Being Prepared for Anything deals with his professional life and work, and with numerous examples from the lead-up to his command of Expedition 35. The book was a New York Times bestseller and was also the bestselling book in Canada on a Canadian subject.

In 2014, his name was added to the Wall of Honour at the Royal Military College of Canada in Kingston, Ontario.

In October 2015, Hadfield released Space Sessions: Songs From a Tin Can, an album of songs that he had recorded on the International Space Station.

In 2017, Hadfield hosted the BBC show Astronauts: Do You Have What It Takes? alongside Kevin Fong and Iya Whiteley, where 12 contestants compete to earn Hadfield’s approval and recommendation as a candidate for future applications to become an astronaut. The challenges involved replicated real tests carried out by the different Space Agencies at facilities in Europe and America, including hypoxia and centrifuge training, with contestants eliminated each week.

In 2020, the newly discovered Andrena Hadfieldi, a species of bee, was named in his honour.