The principal of a troubled Bronx middle school shoved a 14-year-old boy against a stairway wall, repeatedly jabbed his fingers into the teen’s chest, and screamed in his face, “I know you wanna hit me — hit me!,” the youth says in an explosive claim.

Emmanuel Polanco of JHS/MS 80 in Norwood assaulted and humiliated 8th-grader Jeremie Francis last April because he was “on the wrong floor” — even after the boy told the principal he was headed to a music teacher’s room for a guitar lesson, according to the claim.

“I don’t care — get off this floor right now,” Polanco ordered, Jeremie said. But when he stepped into the stairwell — an area without security cameras — the principal “pushed me to the wall.”

Jeremie, 6-foot-3 and 230 pounds, said he told Polanco, “I don’t want to hit you,” but the teen later testified, “I was scared and angry that I let him treat me like that.”

The teen’s story of harassment and retaliation after his mom complained corroborates accounts from several MS 80 teachers that Polanco bullies staff and students he dislikes, while rewarding cronies and favored faculty members.

The Post reported last week that Polanco is under investigation for an incident in which two 8th-grade boys dropped a 6th-grader on his head, causing the child to pass out and have seizures. Polanco and John “Chucky” Perez — his friend and school aide who has acted as a dean — are accused of making the older kids and a staffer who witnessed the attack call it an accident in written statements.

Polanco and Perez are also under scrutiny for allegedly assaulting a 7th-grade girl while trying to yank her phone away, and trying to make her repeat the grade after her mom threatened to sue.

Polanco and Perez have refused to comment. Last week, Perez asked the girl’s mom, Leslie Cruz, to identify the whistleblower who gave Cruz’ phone number to a reporter.

While the city claims MS 80 has significantly improved under Mayor de Blasio’s $582 million “Renewal Program, The Post last week exposed a school with dismal math and English test scores, poor discipline, shoddy building conditions, and administrative cover-ups.

Jeremie’s mother, Hondina Diaz, said Polanco would not meet with her after the April 14 stairwell incident. She then went to the DOE’s Bronx office to complain, but was told to work it out with the principal. She also went to the NYPD’s 52nd Precinct, but when Polanco didn’t show up, cops declined to file a report, she said.

Diaz finally hired a lawyer, who on May 10 filed a notice of claim with the city Comptroller’s office seeking $2 million in damages for assault, battery and “intentional infliction of emotional distress.”

After that, Polanco went after Jeremie with a vengeance, he and his mom said.

On May 19, Polanco and aides surrounded Jeremie when he asked a question during a fire drill, he said. They took him to the office, and held him for an hour — with his arms handcuffed behind his back.

That prompted his lawyer, Todd Crawford, to send a May 23 letter to Mayor de Blasio and Chancellor Carmen Fariña. Begging them to “make it stop,” Crawford wrote that Polanco’s conduct violated Chancellor’s Regulations that forbid physical and emotional abuse of students.

“Bullying is not acceptable behavior for a principal,” he wrote.

Crawford said he got no reply.

After the letter, Polanco yanked Jeremie, who had scored highly on the state’s math and English exams, out of his honors classes and put him in a room with non-English speaking immigrants for the rest of the school year. “I just sat there,” he said.

Polanco also barred Jeremie from playing basketball and baseball after school. He would not let Jeremie join classmates on a trip to Dorney Park or go to the prom.

“It sucked,” Jeremie said, adding that a girl who got into lots of fights attended the prom. His pals shared photos on Snapchat: “I saw them having fun.”

The afternoon before graduation, the school told Jeremie he was barred from the ceremony.

Jeremie had completed all remaining assignments, he and his mom said, but was forced to go to summer school. He scored 100 on the final exams, they said. He then attended an August graduation ceremony at Bronx Science HS with a half-dozen classmates, but they got no caps and gowns — and not one JHS 80 staffer showed up.

Polanco did not answer a request to explain his treatment of Jeremie.

The DOE said it would not comment on pending litigation, but defended the principal, who started at JHS 80 as interim principal in 2012.

“Mr. Polanco has been an effective leader and strong advocate for JHS 80 for nearly six years and is dedicated to supporting the success of all students and staff,” spokesman Douglas Cohen said.

After The Post’s report last week, Polanco held a faculty meeting where teachers praised his leadership, and strongly disagreed with a negative portrayal of the school.

But the meeting got heated when several teachers blasted those who spoke anonymously to reporters.

“They made a fatal mistake,” one is quoted as saying. “Where I’m from, if you do something like that, you’re a rat — and if you stand by a rat, you’re a rat too.”

Banging on a table, he shouted, “I’m calling that person a f–king rat!… You’re a rat! You’re a rat!”

A staffer in the meeting took the words as a threat: “In the mob world, being seen as a rat means you’re going to get whacked.”

Another staffer suspected of speaking to a Channel 2 reporter transferred out after her photo marked with the word “rat” was plastered in a rest room, sources said.

In another meeting, a teachers’ union leader handed out index cards and asked teachers to write opinions about the school — with their names and e-mail addresses — to show higher-ups.

Other JHS 80 staffers collected more than 500 signatures on a Change.org petition, demanding a public apology from The Post for “slander.” The person listed as launching the petition, “Jamie Dunhurst,” is unknown. Records show no one with that last name in New York state.

But another teacher stepped forward to reveal more horrors.

She said she was assaulted twice in the classroom, and administrators ignored it. In one, case, she took a boy’s headphones because he was listening to music instead of working.

“He pushed me to the floor and kicked me,” she said.

A union rep advised her against filing a report or the school “will go after you,” she said. “They don’t care about me, and I could lose my job.”

In another case, she was thrown down when a gang member with a knife broke into the classroom to attack a student, and threw chairs.

The teacher said some colleagues misinterpreted the Post report.

“It’s not about the kids,” she said. “It’s about administrators who lie, cover-up the violence, and don’t provide proper supervision.”

“Where is the accountability?” asked Max Eden, a senior fellow who studies education at the Manhattan Institute think tank. “A guy like Polanco can physically assault kids, but is seen as a star. It sounds like the Mafia — as a ‘made man’ he can just attack kids without consequence.”

Additional reporting by Sara Dorn