Joe Biden played apple-polisher to more than 1,000 unionized teachers in Midtown on Sunday — promising them a “generous” raise if he gets elected to the White House.

The Democratic presidential front-runner also worked the crowd at the United Federation of Teachers-sponsored Teacher Union Day event by expressing support for striking Chicago teachers and pledging to find a way to “wipe out” teachers’ own student debt.

“A whole generation of American teachers deserve a generous raise, and I’m going to make sure they get one,” he said during the event at the New York Hilton Midtown, without providing further details. “The fact is there is no doubt in my mind that if we invest in you, the teachers, there’s not a single nation on earth that’s going to be able to match who we are.”

With an audience that included a large contingent of UFT members — who have yet to endorse a candidate for president — the event had the feel of a political rally.

“Jill and I will be the best partners you’ve ever had in the White House,” Biden vowed, referring to his wife. “We are going to fight to see that you are treated with the dignity you deserve in addition to getting resources.”

He also said a teachers’ strikes like the one underway in Chicago, which entered its fourth day Sunday, “are about more than teacher’s pay, more than about healthcare” — two of the topics at the center of the strike.

“It’s about the things that become possible in our country when our children have the tools they need,” Biden said.

It was music to the ears of many in the audience — although educators who spoke to The Post were not ready to jump on the Biden bandwagon just yet.

“I mean, obviously because we are a union, we want to hear his position on unions and how that works in to his plans,” said UFT member Carlos Olivieri. “Right now everyone is in the courting stages.”