The reigning Olympic champion missed the first two events of the 2012-2013 campaign with injury but she started off this season in style, picking up her 37th career victory in the process.
The 27-year-old scored a total of 25.07 points to beat Justine Dufour-Lapointe of Canada with Aiko Uemura of Japan in third.
"I could not have asked for a more satisfying day. There was something about building your way up," said Kearney. "I was second, then I was third getting into the superfinal.
"This first place and, more than that, winning the way I did gives me a lot of confidence on the Olympic season."
In the men's event, Mikael Kingsbury showed he has maintained the form that clinched him the 2013 World Championship as he topped the medal rostrum once again.
The Canadian scored a total of 26.93 points for his 17th World Cup win ahead of compatriot and reigning Olympic champion Alex Bilodeau in second with 26.54 points and Japan's Sho Endo in third with 25.24 points.