The Atlantic Ocean landing is the first in almost 50 years for a capsule that was designed for humans, NASA says.
The Crew Dragon splashed down at 8:45 a.m. ET, landing at precisely the anticipated time, give or take a few seconds.
SpaceX's Crew Dragon is an upgraded version of the robotic cargo-carrying Dragon that has been ferrying payloads to and from the space station since 2012, a year after NASA retired its space shuttle fleet.
The Crew Dragon spacecraft, flying a mission designated Demo-1, undocked from the station's Harmony module at 2:32 a.m.
SpaceX's recovery ship, Go Searcher, is equipped with a crane to lift Crew Dragon out of the water and onto the main deck of the ship within an hour after splashdown.
The only passenger on Crew Dragon during the current mission was a sensor-laden mannequin named Ripley, dubbed in honor of Sigourney Weaver's character in the "Alien" sci-fi film series.
Significant delays hampered the launch of the Crew Dragon but on March 2 it finally achieved lift-off from storied Launch Pad 39A at Kennedy Space Center. While improvements still need to be made, the company aims to fly NASA astronauts Bob Behnken and Doug Hurley on the next demo flight.
History made: Crew Dragon was the first spacecraft to dock at the space station's new worldwide docking adapter, installed in the Harmony module by astronauts in August 2016.
Crew Dragon's departure burns quickly moved it outside the station's imaginary 200-meter-wide Keep Out Sphere, and in roughly 20 minutes, it was outside the 4-by-2 kilometer approach ellipsoid. Before the mission, Nasa officials had said the spacecraft's ability to dock autonomously to the station would be one of the biggest tests of the vehicle.
Should that mission go well, the next flight of the Crew Dragon will include humans. NASA's timeline hopes that they will have two American companies launching from American soil to replace their Soyuz contract before the end of the year. "And that's cool", Bill Gerstenmaier, the associate administrator for NASA's human spaceflight program, said during a briefing before the launch, The Washington Post reports.
After leaving the station Crew Dragon then spent the next several hours tracking away from the station and getting on track to reenter Earth's atmosphere.
Russia, one of Nasa's key partners on the space station, initially objected, citing concerns with SpaceX's computer systems that would fly the vehicle toward the station.
Three more crew members - Russian cosmonaut Alexey Ovchinin and NASA astronauts Nick Hague and Christina Koch - are scheduled to arrive at the space station aboard a Russian Soyuz crew capsule next week, on March 14.
Once aloft, the SpaceX craft travelled to the space station, whizzing around the Earth at 28,163kmh, catching up early the next morning.