“If I hadn’t gone to Bronx Science, I would have remained within a privileged bubble my whole time in New York City,” he said in a 2016 “Encompassed” podcast, which shares the stories of the school’s graduates. “I love where I’ve grown up, right next to Columbia, but I don’t identify with it as a community.

“What makes Queens feel like home to me is who is there, also the class of individuals,” he said.

In 2014, he graduated with a bachelor’s degree in Africana studies from Bowdoin College in Maine before returning to New York, where he volunteered for a city council campaign and worked as a foreclosure prevention counselor while moonlighting as a rapper known as Young Cardamom.

In 2018, he became a naturalized citizen. In 2020, he ran for the state assembly in the 36th Congressional District, which includes Astoria, one of the most ethnically diverse communities in the world.

“My job is to help families on the brink of homelessness stay in the homes they worked their whole lives to earn,” he said in a 2020 state assembly candidate statement. “Every day, I come face to face with the human consequences of decades of pro-corporate and pro-landlord politics in Albany.

“Every day, I’m reminded that all this suffering isn’t inevitable — it’s a choice that our representatives make to put the interests of their campaign donors over the well-being over their constituents,” he said.

Mr. Mamdani defeated a 10-year incumbent Democrat whose family immigrated to Queens from Greece when she was an infant and who had a similarly liberal platform. He criticized her for endorsing former Secretary of State Hillary Clinton over Sen. Bernard Sanders in the 2016 Democratic presidential primary and Rep. Joseph Crowley in 2018 over activist Alexandria Ocasio-Cortez. He also accused her of being too close to the Queens Democratic Party.

According to a New York Times analysis of his legislative tenure, Mr. Mamdani has introduced about 20 bills and passed three relatively minor measures since arriving in Albany.

The Mamdani campaign did not respond to a request for comment for this article.

The lack of a record has sparked a race to define Mr. Mamdani, who leads in the polls despite having millions of dollars spent on attacks against him.

He is a democratic socialist running on possibility, hope, and ideas aimed at lowering the cost of living. He’s also tapping into the lingering disdain for Mr. Adams, and former Gov. Andrew Cuomo, each of whom have been involved in scandals.

Mr. Mamdani pledges to raise taxes on the wealthy and corporations. He wants to raise the minimum wage to $30 per hour by 2030 and establish city-owned grocery stores.

He has also vowed to bar Immigration and Customs Enforcement from conducting enforcement operations in New York City.

In response, his rivals cast him as a snake oil salesman, arguing his ideas are delusional, and would be a disaster, and focusing on some of his past rhetoric.

They highlight how he refused to say Israel should be a Jewish state, supported the Boycott, Divestment and Sanctions movement, and refused to condemn the “globalize the intifada” slogan.

He also vowed to arrest Israeli Prime Minister Benjamin Netanyahu if he sets foot in New York City.

Mr. Mamdani overcame the attacks in the Democratic primary. He received the endorsement of Mr. Sanders, the democratic socialist and Godfather of the modern far-left movement in the U.S.

Mr. Mamdani also picked up an endorsement from Ms. Ocasio-Cortez. Her victory over Mr. Crowley in 2018 electrified left-wing activists.

Brad Linder, the city’s comptroller and highest-ranking Jewish leader, vouched for Mr. Mamdani in the race, helping him withstand accusations that he is an antisemite.

Mr. Mamdani received a significant boost from the Working People’s Party and the powerful Democratic Socialists of America, whose grassroots army backed Ms. Ocasio-Cortez and helped him raise money and the campaign knock on more than 1.5 million doors.

“My joke has been it felt like it hit a level where like canvassing for Zoran was the new brunch,” said Morris Katz, the lead media strategist for the campaign, this month on the “Pro Politics Podcast with Zac McCrary.”

Mr. Katz said Mr. Mamdani’s rise has a lot to do with him being a generational talent with a unique ability to connect with people on an individual level and distill complex policy ideas into digestible, clear nuggets.

“He just knows who he is. So he is not having to spend the brain power that I think a lot of people have to spend on, like: ’Wait, what do I want to say? Wait, is it bad if I am saying this?’ There is just a comfort level that I think comes through,” he said.

“I also think he is the guy at the party everybody wants to talk to … even if he wasn’t the Democratic nominee for mayor,” he said.

In addition to his charisma and unrelenting campaigning, Mr. Katz said a simple message has helped Mr. Mamdani overcome the inexperienced attacks.

“You may not know what it looks like for Zohran to govern, but we know what it looks like to have Andrew Cuomo or Eric Adams to govern,” Mr. Katz said, adding the message boiled down to: “Good judgment is better than bad experience.”

If elected, Mr. Zamdani will be 34 years old, marking him the youngest New York City mayor since “Boy Mayor” John Purroy Mitchel won the job in 1914.

Mr. Zamdani now faces a fresh round of challenges.

Former Gov. David Paterson and other Democrats are trying to stop him. They are urging either Mr. Cuomo or Mr. Adams to drop out so the anti-Mamdani vote can unite behind a single candidate.

Meanwhile, New York Republicans are doubling down on his lack of experience.

“Zohran Mamdani is unfit for any office, let alone the second hardest job in America,” said New York GOP spokesperson David Laska.

“He stands against everything America stands for: he is openly communist, racist, antisemitic and anti-police,” he said. “If Mamdani becomes mayor, the exodus of businesses and citizens from New York will increase, and the city will spiral into economic decline, lawlessness and division.”