The 29-year-old reigning world champion clocked a combined time of 2 minutes 45.29 seconds. He was joined on the podium by two Frenchmen. Surprise package Steve Missilier came in at 0.48 seconds to take silver, while his compatriot Alexis Pinterault claimed bronze, a further 0.16 seconds off the pace.
"It's unbelievable!” exclaimed a delighted Ligety. “It was the one I wanted to win for so many years.
“The pressure was Huge. Alexis [Pinturault] is one of the big stars of tomorrow. Steve [Missilier] and me, we are the same age, and he deserves his silver.”
Both of the men joining Ligety on the podium were thrilled to have secured their first Olympic medals.
“We knew that we’d have to pull out all the stops in the second run. I still can’t believe what’s happened! It’s a great feeling to be here on the podium with Alexis,” said Missilier, who with just one World Cup podium to his name going into Sochi 2014, was never really expected to feature among the medals.
And Pinturault echoed the sentiment: “This is going to make for a fantastic memory. We were behind Ted, but I am genuinely delighted by this result.”
The competitors completed their two runs against a backdrop of blue skies and glorious sunshine, as Ligety signalled his intentions with a blistering first run that made light of the soft snow.
“Sometimes my best or fastest run doesn't feel like that,” said the four-time world champion after his first run.
“Today, I actually felt at times that I was going a little too cautiously, but I managed to get a nice buffer.”
In truth the American had at times managed to conjure angles and trajectories that seemed to defy conventional geometry.
That left him with a lead of almost one full second going into the second run, with Czech skier Ondrej Bank, a rank outsider before the race, leading a charge of no less than 17 pursuers all finishing the first leg within a second of each other.
That meant that even if the inspired Ligety looked near untouchable for gold, there was a superb battle in store for the other podium places.
Missilier, 10th after the first run, took the lead after an impressive second run and managed to stay on top of the leaderboard as a number of favourites came down the course.
However, Ligety, who had a huge 1.50sec lead on the Frenchman after the first run, could not be caught as he raced out of the gate in 30th place for his second run.
The giant slalom has long been Ligety’s favourite discipline, accounting for two of his four world titles to date.
However, he had never previously enjoyed much success in the event at on the Olympic stage, failing to finish in Turin and coming in ninth place at Vancouver 2010.
His performance in giant slalom in Sochi banished the disappointments of the super combined and super-G, in which he finished 12th and 14th respectively.
For 22-year-old Pinturault the bronze represented his first major medal, and was deserved reward for a season that has been sweet with the smell of future success.
The young Frenchman had started the race among the favourites with Ligety and Austrian hot shot Marcel Hirscher, the current giant slalom World Cup leader, who fell short of the podium by 0.30 seconds.
Defending Olympic champion Carlo Janka of Switzerland was 13th, while Norway's Kjetil Jansrud, giant slalom silver-medallist in Vancouver, who was looking to add a third Sochi medal to his super-G gold and downhill bronze, skied out.