With results in from more than 96% of districts, Sliwa had collected 36,668 votes, or support from nearly 69% of the city’s GOP voters, according to the New York City Board of Elections.
"I am a populist," Sliwa told about 200 supporters after the race was called, with Rudy Giuliani, a former Republican mayor of New York City, standing beside him. "I am not omnipotent and pretentious like a lot of the elected officials who are running for higher office. I have to undo what this part-time mayor Bill de Blasio has done to all of us, Democrats, Independents and Republicans. He has taken a wrecking ball to this city that we love. Destroyed it."
Sliwa vowed to fight crime, address the city’s homelessness problem and stop animal shelters from euthanizing pets.
"Curtis won and we want to unite the Republican Party and we hope Fernando Mateo will join us," Sliwa campaign adviser Rob Cole told the New York Post, referring to Sliwa’s top GOP competitor.
During a campaign event in April, Sliwa called for refunding the city's police department by restoring $1 billion that the city council had shifted from police to education and social services programs.
Mateo, a restaurant owner and advocate for bodega owners and taxi drivers, collected 14,328 votes, or nearly 27% of those counted so far, the elections board said.
Sliwa, 67, a native of the city, first gained attention in May 1977, when he formed the Magnificent 13, a group that later became the Guardian Angels. As the city struggled with crime in that era, members of Sliwa’s group would fan out across the city, in parks and on subways, in hopes of deterring crime.
The Republican’s mayoral run received endorsements from Giuliani and from U.S. Rep. Nicole Malliotakis, the only member of Congress from New York City who is a Republican, the Post reported.
On the Democrat side, Brooklyn Borough President Eric Adams appeared to be leading early Wednesday but final results were expected to remain unclear, possibly for weeks, The Associated Press reported.
Current Mayor Bill de Blasio, a Democrat, was barred from seeking a third term because of the city’s term limit law.
Fox News' Tara Prindiville contributed to this story.