Chicago’s top cop had “a couple of drinks” before he was found slumped over asleep in his car at a stop sign — but his officers let him leave without any tests, the city’s mayor has revealed.

Superintendent Eddie Johnson, 59, had called for an internal affairs investigation into himself after he was found asleep in his car close to home in the early hours Thursday.

The police leader, on a $260,044-a-year salary, blamed new medication for the scandal — but later admitted to drinking before trying to drive home, Mayor Lori Lightfoot told the Chicago Sun-Times.

“He revealed to me that he had a couple of drinks with dinner,” Lightfoot told the paper.

The mayor refused to speculate on whether Johnson — who was not tested for his alcohol level by his officers, who let him continue driving home — was fit to drive.

“I can’t say that. I don’t think you can say that. But no matter what, we’ve got to let the investigation play itself out,” Lightfoot told the Sun-Times.

“He’s a grown man. He had a couple of drinks with dinner,” the mayor added, stressing how important the investigation was.

“Everybody — whether it’s the superintendent or a beat patrol officer — has to abide by the rules.

“It was the right thing to call for an investigation … We’ll see how that plays itself out,” the mayor told the paper.

“I want to give him respect. We will see what the circumstances are. … We’ll see where the facts take us.”

The top cop had earlier admitted dismissing his driver over dinner so he could go home to his family, saying, “Should I have had a driver with me last night? Yes, I should have.”

He also defended his officers’ decision not to test for whether he had been drinking — in comments made before the admission he had some alcohol in his system.

“Someone asleep in a car doesn’t mean they’re impaired,” Johnson had told reporters, according to the Chicago Tribune.