"It was a tough race and I had to be really prepared to give it everything and do what I could because the competition was so strong," Carrington said. "I couldn't leave anything to chance. I'm just really pleased to get the K1 500m done and now I can refocus on the 200m."
Carrington became just the second non-European to win the K1 500m title, after Canada's Caroline Brunet from 1997-99. It was first raced in 1938.
Kárász, who posted the fastest semifinal time a day earlier, stuck with Carrington for the first half of the race, trailing by 0.650secs at the 250m mark but had no answer when the Kiwi powered home over the final stages.
The win completes a seamless 500m progression for the New Zealander, who finished third in 2013 and second last year.
If she wins the K1 200m tomorrow, Carrington will equal Brunet as the most successful sprinter in history. Brunet was the last women to hold both titles in the same year, although that was before the shorter race was an Olympic discipline.
Poland's Marta Walczykiewicz, who has been runner-up to Carrington for the last three years, again looms as her main rival.
The men's K2 of Zac Franich and Darryl Fitzgerald finished seventh in their 1000m C final. The New Zealand women's K4 raced their semifinal overnight.