An NYPD officer catching a nap in his car between two New Year’s shifts took a random bullet to the head outside a Harlem precinct house early Saturday, authorities said.

The officer awoke in the parking lot outside the 25th Precinct stationhouse to find the window of his personal vehicle shattered and blood dripping from a painful head wound, police said. He was taken to New York Presbyterian Hospital, where a bullet fragment was removed from his fractured skull, authorities said.

He was expected to make a full recovery from the bizarre shooting, as the closed window absorbed most of the impact. New Mayor Eric Adams, in his first day on the job, promised to rein in the citywide gun violence under his administration.

“This is not going to be a city of disorder, this is not going to be a city of violence,” said the ex-NYPD captain. “This city is returning from the violent past to a place that is safe to raise our children and families.”

According to NYPD Chief of Detectives James Essig, the officer was awakened around 6:15 a.m. by rain coming through the broken glass and quickly felt the pain in his head. When the cop got out of the car, he and a sergeant found the deformed bullet.

The officer was asleep inside the lot on E. 119th St. after finishing an eight-hour New Year’s Eve shift in Central Park around 2 a.m., with a second tour set to begin at 7 a.m. Police officials said he opted to sleep in his car because the precinct’s dormitory was full.

The cop, whose wife was with him at the hospital, was not the target of the gunshot — which was likely fired from some distance away, said new Police Commissioner Keechant Sewell. Bullet fragments were pulled from the car as well as his head, and she added there were no 911 calls for a gunshot nor did any officers outside the precinct hear anything..

“We are extremely grateful that our officer is recovering as we know this could have been a very tragic outcome,” said Sewell, who has vowed to bring down gun violence in the five boroughs. “I also do believe this incident underscores that there are far too many guns out there in the wrong hands.”

Cops were searching the area for video and checking area rooftops for ballistic evidence. The shot came through the rear driver’s side window as the cop slept behind the wheel.

The precinct parking lot was roped off as detectives collected evidence. No arrests have been made.

Pat Lynch, the president of the Police Benevolent Association, the city’s largest police union, said the shooting “shows the magnitude of the issues and the problems we face.”

“He was in a police parking lot and was still shot,” Lynch said. “It shows us the dangers police officers face always.”