Walsh had earlier surprised many to make the final with a 20.40, which placed him sixth, after going into the competition ranked 17th. Starting the final with two fouls, Walsh threw 20.12 in the third round, before improving to 20.46 in the fourth round, then 20.88 and 21.26.
Walsh commented after the competition that he knew he was in good shape after a week training with world champion Valerie Adams and coach Jean Pierre Egger in Switzerland, but he was somewhat surprised with the distance and placing achieved.
Remarkably, the world champs were not only Walsh's first senior international competition, but also his first ever indoor competition.
At the same time on the track, Zane Robertson led for most of his 3000m heat before finishing in sixth place with a time of 7:44.16, beating Nick Willis' national record and qualifying for Monday morning's final.
Robertson's effort completed an outstanding day for the Kiwis in Sopot, with Willis having earlier looked very comfortable in qualifying for the final of the 1500m. Valerie Adams competes in the shot put qualifying this evening, with the final scheduled for early on Sunday morning (NZT).