JPMorgan Chase CEO Jamie Dimon cautioned Mayor Zohran Mamdani about his hard-left vision for the Big Apple, warning the millennial mayor that he can relentlessly preach morality and ideology — but if the city keeps struggling, he’s failing to do his job.

“I don’t care what he says. What does he do? I will judge that … because you can talk about morality and ideology all you want, but if things don’t get better, you didn’t do a good job,” the Wall Street titan told Bloomberg TV Thursday.

“And my view, and I’m talking about him now, I have seen mayors who make statements, and they make it worse and worse and worse, you know, and they don’t know, they can’t get into details of why is affordable housing not there anymore? Why does this not work?

“And so, you know, hopefully he’ll learn. I want him to do a good job.”

Dimon’s biting comments came after he and other top business leaders met with Mamdani, who has pushed a slate of tax hikes targeting the wealthy and businesses since taking office in January.

The 34-year-old Democratic socialist — who campaigned on a tax-the-rich agenda — has proposed jacking up corporate taxes, socking millionaires with a new 2% income tax hike, and slapping a luxury levy on second homes worth over $5 million across Gotham.

The 70-year-old savvy businessman warned that only time will tell whether Hizzoner’s ambitious lefty politics drive away the people and companies New York needs to survive and grow.

“Every city has to compete, and they have to compete at every level — arts, science, schools. That is what it is, I’m not inventing that,” Dimon, a Queens native, insisted.

“He can be an ideologue, but he has to compete too, and we’ll see. Will he learn that he’s got to make the city a place where people want to grow and build and live and have families and work?” he added, pointing to global powerhouses like Shanghai, Hong Kong, Singapore, and Nashville, Tenn.

“And people vote with their feet.”

During the interview, Dimon threw his support behind Jeff Bezos’ view that lower earners shouldn’t be hit with income taxes.

The Amazon founder called for changes to the US tax system, which he said sees the top 1% already pay 40% of all taxes while the bottom half contributes 3% — stressing that taxes for lower earners should be slashed to “zero,” during a Wednesday sit-down with CNBC.

“I saw Jeff Bezos, who I love, swashbuckling,” Dimon raved.

“I don’t think the lower people making under a certain amount [should be] paying taxes at all, you know, I would agree with that.”

He also backed the Blue Origin founder after he slammed Mamdani for casting billionaire Ken Griffin as a “villain” in a bizarre video the mayor filmed outside his Manhattan apartment last month.

The April 15 video stunt sparked backlash from business owners and city leaders when Hizzoner called out the Citadel head by name and used his record-setting $238 million Midtown penthouse as a backdrop to tout a new pied-à-terre tax.

“I think he realized he made a mistake in naming Ken, and vilifying a name and a person,” Dimon said.

“It’s probably why he’s seeing a bunch of us now. He’d like to maybe have a better relationship with the business community.”