Zohran Mamdani is poised to become the Democratic nominee for New York City mayor, after leading in the city's ranked-choice primary on Tuesday.

The 33-year-old state assemblymember and democratic socialist was virtually unknown when he jumped into the crowded primary field last fall. But he had recently skyrocketed in the polls, fueled by in-person interactions, viral videos and policy proposals that appear to have resonated especially among younger and first-time primary voters.

"I think everyone is stunned and shocked by the unexpected nature of his victory," says Patrick Egan, a professor of politics and public policy at New York University. "And I think one of the other notable things about that victory is that he won with a really progressive, liberal left-wing platform of the kind that we probably haven't ever seen in New York."

With 93% of precincts reporting, Mamdani garnered 44% of ballots — the most of the 11 candidates and far more than the 36% of former Gov. Andrew Cuomo, the one-time frontrunner. Cuomo conceded to Mamdani on Tuesday night, but has left the door open to run as an independent in November's general election.

The primary isn't officially over: The losing candidates' ballots must be redistributed to voters' second-choice candidates until one of them breaks the 50% threshold, a process that is set to begin on July 1.

But Mamdani's commanding lead sent a clear message — and was enough for him to declare victory just after midnight.

"I will be the mayor for every New Yorker, whether you voted for me, for Gov. Cuomo or felt too disillusioned by a long, broken political system to vote at all," Mamdani told supporters at his Long Island City watch party. "I will fight for a city that works for you, that is affordable for you, that is safe for you."

If Mamdani does win the primary, he will face off against a slew of candidates in November — including Republican nominee Curtis Sliwa, who ran unopposed in his party's primary, and embattled Mayor Eric Adams, who bypassed the Democratic primary by announcing he'd seek reelection as an independent.