The four-times World Cup overall champion, and 2010 Olympic downhill champion, was fastest at every intermediate stage on the Kandahar course as she finished 0.15 seconds ahead of Switzerland's Lara Gut. Germany's Viktoria Rebensburg was third.
The 32-year-old American made her comeback at Altenmark-Zauchensee last Sunday when she finished 13th in the downhill.
“I’m so happy that it only took me two races to get back on the top step,” said Vonn, who was 17th on the start list.
“Honestly, I wasn’t sure after Zauchensee how long it would take me. I proved to myself today that all the work that I put in is really coming through.”
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It was Vonn's 77th win in a World Cup race, leaving her nine short of the record set by Sweden's Ingemar Stenmark.
“I’ve worked really hard to come back and I feel like sometimes I come back so quickly that everyone forgets how much time and energy, blood, sweat and tears it takes to come back without any training and just jump in there," said Vonn.
"I just had to trust myself, my team and my technician."
Vonn suffered a knee injury in Andorra late last February and then broke her arm in training in Colorado in November, requiring an intensive program of rehabilitation. She also suffered lingering nerve damage.
Gut, last year's overall World Cup winner, is second this year and trimmed American Mikaela Shiffrin's lead to 235 points. Shiffrin, a slalom specialist, did not take part in Saturday's race.
(Writing by Brian Homewood in Berne, editing by Pritha Sarkar)
