Ms Goggia timed 1min 39.22sec for a first downhill title in the women's blue riband event.
The 25-year-old came in 0.09sec ahead of Norway’s Ragnhild Mowinckel, with the US’ Lindsey Vonn a further 0.42sec behind.
Ms Goggia made a mistake on the upper part of the polished 2.8-kilometre-long Jeongseon course, but produced a superb gliding mid-section and strong bottom third.
It reaffirmed the fine form she has shown on the World Cup circuit this season, with two victories and two second places in the downhill, and also second and third placings in the super-G.
Ms Goggia joins snowboarder Michela Moioli and short track speed skater Arianna Fontana as Italy's gold medallists in the 2018 Winter Olympics.