The Kiwi dominated the competition in Birmingham from start to finish, opening with an Oceania indoor record of 22.13m. He fouled his second attempt and then again recorded 22.13m in the third round, leading by 90cm as the top eight advanced to the fourth round.
The chasing pack closed the gap without ever threatening Walsh's mark. Germany's David Storl, a former two-time world outdoor champion, improved to 21.44m to clinch silver on a countback ahead of Czech Tomas Stanek in third.
Brazilian Darlan Romani placed fourth with 21.37m, twice extending the South American record.
Knowing he had the gold medal in the bag as he headed to the circle for his sixth and final effort, Walsh unleashed a monster put of 22.31m, the longest of his career.
That was good enough for him to win the competition by 87cm and eclipse the championship record of 22.24m set by German Ulf Timmerman at the first world indoor championships in 1987.
The 26-year-old Kiwi will be eyeing the world indoor record of 22.66m, held since 1989 by American Randy Barnes, and will be the hottest of favourites at next month's Commonwealth Games. The world outdoor record is 23.12m set by Barnes in 1990.
Meanwhile, Kiwi Pole vaulter Eliza McCartney finished out of the medals but showed she's back in the frame among the leading competitors on the globe.
Rio Olympic bronze medallist McCartney sat second at one point, then third but when she dropped the bar for a third time at 4.80m she could go no further.
American Sandi Morris cleared at 4.80m and then Olympic champion, Greece's Ekaterini Stefanidi, did the same in a high pressure moment to move into third and bump McCartney down to fourth.
Russian Anzhelika Sidorova was the surprise leader as the event reached it's climax.
McCartney, 21, had the satisfaction of having produced a personal best height of 4.75m in indoor competitions. Her outdoor PB is 4.82m set last year.
McCartney cleared 4.50m at her second attempt, 4.60m at the first try, then 4.70m with her third and final jump, in a tense situation, before flying over the bar at 4.75m, squealing with delight.
But 4.80m was a touch too far.
