De Blasio's fork, which he used to chow down on a slice at Goodfella's Pizzeria on Hylan Boulevard, was bought for $2,500 by an uknown bidder after pizzeria co-owner Marc Cosentino put it on the auction block.
The proceeds from the sale will be donated to the Stephen Siller Tunnel to Towers Foundation.
"It's a good cause, and it's a nice piece of New York history to have," Cosentino said.
Bidding on the fork started at $1,000 from Cosentino, who said he still plans to make a donation to the charity. Three others also vied for the utensil, with an unidentified person online making the winning offer.
During a campaign stop in the pizzeria in January, de Blasio whipped out a knife and fork to eat his slice, causing an immediate backlash online from people critiquing the mayor's pizza technique.
"What are you doing?! I have to teach you everything?!" Stewart shouted after de Blasio pulled out utensils. "With your hands!"
After the meal, Cosentino, a retired NYPD sergeant, places the fork in an evidence bag and put it on display behind the bar in his restaurant.
"I just did it because I thought it was funny," Cosentino told DNAinfo New York. "Then all of a sudden it got all this interest, so I thought let's do something, let's do something for charity."
He said people came from all over to take pictures with the fork, and he chose the Tunnel to Towers foundation to help it continue its work for Hurricane Sandy recovery and building homes for disabled veterans.
While many New Yorkers blasted the mayor for not using his hands, Cosentino said it wasn't that uncommon to see people use a knife and fork in his shop.
"So long as people are eating pizza, doesn't matter how they eat it," he said.