The 17-year-old put down a clean run on the two-rail, two-jump course yesterday (NZ time).
He laced together a front blunt, 450 out into a cab 270 on, 450 out on the two rails.
On the jumps he stomped a switch backside double corked 1260 into a frontside 1080 to be rewarded with a score of 87.00.
“It feels great, I am blessed to be able to come to Italy and compete here at the Junior World Championships and get a medal in slopestyle,’’ Jamieson said.
‘‘It has been pretty tough with the weather this season in Europe for training, but I got some good time competing and training at the Silvaplana World Cup last week so I was ready to compete here.
“The course was amazing, the jumps and the rails were really well built - it’s a sick park here.”
Brooklyn Depriest, of the United States, won gold with a score of 91.00 and Romain Allemand, of France, finished second with a score of 89.00.
Kiwi Txema Mazet-Brown, of Raglan, finished in seventh place.
It is Jamieson’s second junior world championships medal in the past 12 months.
He also secured a silver medal in big air at the FIS Park and Pipe World Championships held at Cardrona in August last year, as part of the Winter Games New Zealand.
There are five Kiwi athletes representing New Zealand at the 2024 Big Air and Slopestyle Junior World Champion ships - Brodie Bamford is also competing in the snowboard events and brothers Fletcher and Fergus McArthur are competing in the freeski events.
The FIS Slopestyle and Big Air Junior World Championships continue tomorrow (NZ time) including snowboard big air qualifications, followed by the freeski big air qualifications on Saturday.
Finals will be held on Sunday.
