The company's Crew Dragon capsule, Endeavour, streaked into the darkened pre-dawn sky atop a SpaceX Falcon 9 rocket as its nine Merlin engines roared to life at 5:49 a.m. (0949 GMT) from NASA's Kennedy Space Center at Cape Canaveral, Florida. The blastoff was aired live on NASA TV.
The crew is due to arrive at the space station, which orbits some 250 miles (400 km) above Earth, early on Saturday following a flight of about 23 hours.
Within 10 minutes of launch, the rocket's second stage had delivered the crew capsule to Earth orbit, traveling at nearly 17,000 miles per hour, according to launch commentators.
The rocket's first stage, meanwhile, descended back to Earth and touched down safely on a landing platform floating in the Atlantic on a drone ship affectionately named Of Course I Still Love You.