Dr. Garrett Reisman was selected by NASA as a mission specialist Astronaut in 1998. His first mission was aboard the Space Shuttle Endeavour, in 2008, which dropped him off for a 95 day mission aboard the International Space Station after which he returned to Earth aboard the Space Shuttle Discovery. His second mission was aboard the Space Shuttle Atlantis, in 2010, and returned Dr. Reisman to the Space Station. During these missions, Dr. Reisman performed 3 spacewalks, operated the Space Station Robot Arm and was a flight engineer aboard the Space Shuttle. After leaving NASA in 2011, Dr. Reisman joined SpaceX where he worked for Elon Musk and prepared SpaceX for human spaceflight as the Director of Space Operations. Currently he is a Professor of Astronautical Engineering at USC and a Senior Advisor at SpaceX.

In June 2003, Reisman served as an aquanaut during the NEEMO 5 mission aboard the Aquarius underwater laboratory, living and working under water for fourteen days.

Dr. Reisman was interviewed multiple times by Stephen Colbert on the 'Colbert Report' TV show. Reisman was also the first Jewish crew member on the International Space Station. He sent a greeting from space to the people of Israel during the celebration of Israel's 60th Independence Day in May 2008. He also did an entertaining, high definition video of "A day in the life of a space station crew member" while on board as well as demonstrating in the large, and at the time empty, Kibo module, that humans cannot "swim" in the microgravity of orbital space.

On March 4, 2011, SpaceX announced that Garrett Reisman would be joining the company as a senior engineer. He was subsequently promoted to be the Director of Space Operations for SpaceX. On May 31st, 2018, Reisman announced he would leave his Director position at SpaceX, but remain a Senior Advisor while becoming a professor at the nearby University of Southern California where he is now teaching engineering courses on human spaceflight.