The 30-year-old was in a class of her own, going quickest on both her runs to win by 1.66 seconds for her ninth career win in Levi and a record-extending 102nd World Cup victory.
Albanian Lara Colturi was second on her 19th birthday, while fellow youngster Emma Aicher of Germany was third for the first World Cup slalom podium of her career.
Shiffrin's victory looked assured from the moment she put down what she described as a 'near perfect' opening run that gave her an advantage of more than one second.
She was spotless again on her second run through the gates to add a ninth reindeer to her herd -- the traditional prize for winners of the slalom event in the Arctic Circle resort.
"I trusted the training and the great work over the summer," said Shiffrin, who will be going for a third Olympic gold medal at the Milano-Cortina Games in February.
"It was really nice to race today. This season it's important to start with a really good mentality. I'm just super happy. This is starting to feel more like home."
With Shiffrin sidelined for a large chunk of last season because of an abdominal injury sustained in a bad crash in Killington, Croatia's Zrinka Ljutic won the World Cup slalom title from Swiss Camille Rast.
But any suggestion that the baton was passing to the younger generation was dismissed by Shiffrin in ruthless fashion on Saturday as she showed that she is still at her peak.
Italian-born Albanian Colturi looks one of those capable of challenging Shiffrin after two impressive runs, even if she will have to wait a while longer for her first World Cup win.
All-rounder Aicher was also impressive as she completed the podium while American Paula Moltzan made up 15 places on her second run to finish joint fourth with Germany's Lena Duerr.
It has been an impressive start to the season for Moltzan who was runner-up in the season-opening giant slalom in Soelden.
Ljutic had to settle for sixth place while slalom world champion Rast was a disappointing 15th.