In the roughly five years since Zohran Mamdani first started campaigning for public office, he has argued that prostitution should be decriminalized. He has called to defund the police. He has said that billionaires should not exist, and that the admissions test for New York City’s elite public high schools should be abolished.

But before he launched his long-shot bid to become the Democratic nominee for mayor last year, he abandoned some of his most provocative views. And during the course of the campaign, he has sought to downplay others.

In the past several days, as Mr. Mamdani has faced mounting pressure from some of his rivals in the four-way general election, he has also tried to distance himself from the platform of the national Democratic Socialists of America, of which he is a member.

His changed positions — and shifting political strategy — come as Mr. Mamdani, 33, seeks to persuade New Yorkers that, despite his relative inexperience, he is ready to lead the nation’s largest city.

His supporters and those who have met with him behind closed doors describe him as open-minded and eager to find common ground. Some in the business community say they have been pleasantly surprised by his pragmatism.

But his opponents have accused him of political opportunism, and suggested he cannot be trusted to handle public safety and New York City’s roughly $100 billion budget.