The Czech athlete - who also picked up gold in Alpine skiing - becomes the first athlete ever to win both those events at a Winter Olympic Games.
After riding the high of an unexpected win in super-G, Ledecka went into parallel giant slalom finals with a qualification time of 43.42 seconds, fast enough to beat almost a quarter of the men's field on the same course.
"It feels nearly unbelievable, but we came out here with great intensity and just had to believe we could do it, and make our shots", said America's Matt "Ham" Hamilton. "A lot of people were telling me that it is not possible to do both sports and to be on a high level in both sports and today I proved it is possible", she said.
"It was quite tough to change myself back into a snowboarder", said Ledecka, already the first athlete to compete in snowboard and alpine skiing at a Winter Olympics. Ledecka finished first in the women's super-G in Alpine skiing, finishing several spots ahead of the decorated American skier Lindsey Vonn.
However, she only started on the skiing circuit in 2016. Even her snowboard coach, Justin Reiter, the former U.S. snowboarder, doubted as recently as last fall that Ledecka could perform at a high level in both.
One of the best things about the Winter Olympics is always the unlikely stories that are written.
But she confessed it had not been easy to deal with the pressure of having so many great expectations on her shoulders.
Justin Reiter, the snowboard coach who came on board this season after ending his own career, said he learned pretty early on not to try and stifle Ledecka's ambition.
"I realized that was really inhibiting what we were doing in that the more I wanted her to find that medal, I really stifled what could be".
A quarter-final victory over Daniela Ulbing was followed by a semi-final win against Hofmeister, who had pushed her all the way before stumbling.
"We did the best that we could to try to shelter her from you guys picking her bones clean". Her lifelong aspiration wasnt simply to go to the Olympics. "I will just go to bed because I'm quite exhausted".
Ledecka revealed that it felt odd to go back-and-forth between the snowboard and skis.
"Today was a big day for snowboard Ester!". She's got a great heart, great head, too. When she looked up at the scoreboard and saw the time, she froze.
CROSS COUNTRY SKIING: Iivo Niskanen beat out Russian rival Alexander Bolshunov with a strong sprint in the 50-kilometer mass start to give Finland its first gold.
Even though you are the only one with a gold medal in two different sports?