Mayor Adams was loudly booed when he mentioned his former career as an NYPD cop during his City University of New York School of Law graduation speech Friday as dozens of students turned their back on him, footage shows.

Hizzoner was waxing about how some law school graduates would go on to become a “public figure” like himself when the crowd erupted into heated heckling, according to video of the outburst posted on Twitter.

“Let’s be clear, for 22 years of my life, I wore a bulletproof vest and protected the children and families of this city as a police officer,” Adams said — prompting a booing along with a smattering of applause.

Near the front of the stage, several rows of students in caps and gowns stood with their backs turned to the mayor, who charged on with the rest of his short speech.

“Just as you see these graduates here, I know what it is to protest,” he said.

“I protested when Amadou Diallo … I protested as 100 Blacks in Law Enforcement Who Care,” Adams said, referencing the unarmed 23-year-old Guinean student who was killed by NYPD officers in 1999.

“But I’m not the mayor because I know how to protest. I’m the mayor because I know how to speak on behalf of the countless number of people in this city,” he said.

The student protest came as the NYPD faced criticism over delaying the arrest of former-Marine Daniel Penny in the chokehold killing of homeless straphanger Jordan Neely.

Penny was charged with manslaughter on Friday, nearly two weeks after he put Neely in a chokehold on an F train and held him there for several minutes, killing him.

“At the CUNY law school graduation ceremony, and when it was announced that Eric Adams will be speaking everyone booed,” tweeted Twitter user @ilissilia. “The new grads did not disappoint during the speech. Lots of heckling, most grads turned their backs.”

It wasn’t clear if the mayor’s CUNY School of Law speech was cut short by the protest. A rep for Adams didn’t immediately return a request for comment Friday.

In 2017, hundreds of NYPD officers turned their backs on former Mayor Bill de Blasio at a funeral for slain officer Miosotis Familia. The gesture was meant to protest an ill-timed trip de Blasio took to Germany following the veteran cop’s death.

De Blasio was also met with a similar “wall of blue” at a 2014 funeral for Officer Rafael Ramos.