The three-day mission ended as the SpaceX crew Dragon capsule, dubbed Resilience, parachuted into calm seas around 7:00 pm EDT (2300 GMT), shortly before sunset, following an automated reentry descent, as shown during a live SpaceX webcast on its YouTube channel.
Within an hour the four smiling crew members were seen emerging one by one from the capsule's side hatch after the vehicle, visibly scorched on its exterior, was hoisted from the ocean to the deck of a SpaceX recovery vessel.
Each of the four stood on the deck for a few moments in front of the capsule to wave and give thumbs-up before being escorted to a medical station on board for checkups at sea. Afterward they were flown by helicopter back to Cape Canaveral for reunions with loved ones.
The return from orbit followed a plunge through Earth's atmosphere generating frictional heat that sent temperatures surrounding the outside of the capsule soaring to 1,900 degrees Celsius. The astronauts' flight suits, fitted to special ventilation systems, were designed to keep them cool if the cabin heated up.
Applause was heard from the SpaceX flight control center in suburban Los Angeles as the first parachutes were seen deploying, slowing the capsule's descent to about 25 kilometre per hour before splashdown, with another round of cheers as the craft hit the water.
The astronauts were cheered again as they stepped onto the deck of the recovery ship.
First out was Hayely Arceneaux, 29, a physician assistant at St Jude Children's Research Center in Tennessee, a childhood bone cancer survivor herself who became the youngest person ever reach Earth orbit on the Inspiration4 mission.
She was followed in rapid succession by geoscientist and former NASA astronaut candidate Sian Proctor, 51, aerospace data engineer and Air Force veteran Chris Sembroski, 42, and finally the crew's billionaire benefactor and ‘mission commander’ Jared Isaacman, 38.
"That was a heck of a ride for us," Isaacman, chief executive of the e-commerce firm Shift4 Payments Inc, radioed from inside the capsule moments after splashdown. "We're just getting started."
The Inspiration4 team blasted off on Wednesday from the Kennedy Space Center in Cape Canaveral atop one of SpaceX's two-stage reusable Falcon 9 rockets.