Dave Williams was an emergency physician in Toronto and Director of the Department of Emergency Services at Sunnybrook Health Sciences Centre prior to his selection by the Canadian Space Agency in 1992. He was one of four successful astronaut candidates from a field of over 5300 applicants. He completed basic training, and in May 1993, was appointed manager of the Missions and Space Medicine Group within the Canadian Astronaut Program.

 

In January 1995, Williams was selected to join the international class of NASA mission specialist astronaut candidates. In April 1998, he participated in STS-­90 as flight engineer, Mission Specialist 3 and crew medical officer aboard the Space Shuttle Columbia. During the 16-day mission dedicated to neuroscience research, the seven-person crew served as both experiment subjects and operators for 26 individual life science experiments.

 

From July 1998 until September 2002, he held the position of Director of the Space and Life Sciences Directorate at the Johnson Space Center in Houston, Texas. With this appointment, he became the first non-American to hold a senior management position within NASA. He concurrently held a position as the first deputy associate administrator for crew health and safety in the Office of Space Flight at NASA Headquarters in 2001.

 

He became an aquanaut through his participation in the joint NASA-NOAA (National Oceanic and Atmospheric Administration) NEEMO 1 mission, a training exercise held in Aquarius, the world's only underwater research laboratory. During this seven-day exercise, Williams became the first Canadian to have lived and worked in space and in the ocean. Subsequently in 2006, he led NEEMO 9 as the crew commander of an 18-day mission dedicated to assessing technologies and protocols for remote medical care. 

 

His second spaceflight on STS-118 took place August 8-21, 2007. During the mission Endeavour's crew successfully added the S5 truss segment, a new gyroscope and an external spare parts platform to the International Space Station. Williams participated in three of a total of four spacewalks (EVAs) and was the lead spacewalker in two of the three EVAs. Traveling 5.3 million miles in space, the STS-118 mission was completed in 12 days, 17 hours, 55 minutes and 34 seconds. 

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A veteran of two space flights, STS-90 in 1998 and STS-118 in 2007, Dave Williams has logged over 687 hours in space including 3 spacewalks (EVAs) totaling 17 hours and 47 minutes establishing the record for the most spacewalks by a Canadian astronaut. Dave Williams retired from active astronaut status in 2008 and through 2011 he held various positions including Chief Medical Officer for Safety and Quality at St. Joseph’s Healthcare Hamilton, Professor of Surgery Faculty of Health Sciences at McMaster and Director of the McMaster Centre for Medical Robotics. 

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From 2011 to 2017 he was President and CEO at Southlake Regional Health Centre in Newmarket Ontario, where he led a dynamic team of 4500 staff and volunteers dedicated to providing safe, high quality medical care to create the ultimate patient experience. He retired from Southlake and is currently consulting in the healthcare and aerospace sector, speaking, and writing. He has written four children's books and has published his memoir Defying Limits: Lessons From the Edge of the Universe with Simon and Schuster. He is currently working on 3 new books which should be available in 2021.

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He is a member of the Canadian Aviation Hall of Fame, has received five honourary degrees, numerous other awards and most recently was appointed to the Order of Canada and the Order of Ontario.