Shiffrin, the dominant female slalom skier on the World Cup circuit over the past two years, became the youngest champion of the event in the history of the Olympics.
She built a lead of .49 of a second lead over Germany's Maria Hoefl-Riesch after the first trip down the course, but when the American set out on her second run the time she had to beat had been turned in by Marlies Schild of Austria.
Schild had the quickest time in the second run and was on top of the leader board when Shiffrin took her turn.
All Shiffrin had to do was come within 1.34 seconds of Schild's second effort and in the end it was not close. Shiffrin won the gold medal by .53 of a second over Schild while Kathrin Zettle of Austria took third place. Hoefl-Riesch finished fourth.
Shiffrin's second run through the final gates was perfect, but just before reaching the midway point of the course her left ski came well off the snow and she traveled several yards balancing herself on one ski.
Once her left leg settled back into the proper position, however, Shiffrin was on her way with only a minimal loss of time.
Shiffrin became the first American medalist in the women's slalom since Barbara Cochran won gold in Sapporo 42 years ago.