Chmielewski touched in at 1:49.26 in Thursday's final, setting a new national record for the 200m butterfly in a 25-metre pool.
Canada's Ilya Kharun claimed gold with a time of 1:48.24, while Italy's Alberto Razzetti took silver with 1:48.64, Polish state news agency PAP reported.
The 2024 World Short-Course Swimming Championships in Budapest run until Sunday.
Poland won two medals, a silver and a bronze, at the 2022 World Short-Course Swimming Championships in Melbourne, Australia.
(gs)
Source: IAR, PAP