The 11-year-old posted her best run in the final round (58.13) to finish third on an all-teenage podium.
Japan’s Misugu Okamoto, 13, topped the standings (61.17) ahead of compatriot Sakura Yosozumi (60.00).
Brown is hoping to become Team GB’s youngest summer Olympian when skateboarding makes its Olympic debut in Tokyo next summer.
GB's Brown, 12, second in Olympic qualifier on return from horror injury
"I am so, so stoked right now," said Brown. I just went out there today and had fun, I can’t believe I got third place, I was really happy just to skate with all these amazing girls from around the world.
I really want to go the Olympics and just show other girls out there that you can do anything, no matter how old you are.
Image credit: Getty Images
Elsewhere, Shaun White suffered a major setback in his bid to win medals at Summer and Winter Games after finishing 13th in the semi-finals of the men’s park competition.
The three-time Olympic halfpipe champion saw three other Americans reach the final, with no more than three men allowed to qualify from each country for Tokyo.
Horrific crash motivated me to push harder - Sky Brown
Skateboarding: New sport on the block in Tokyo