Chicago police Superintendent Eddie Johnson will announce Thursday morning that he will retire.

Anthony Guglielmi, the department’s chief spokesman, confirmed a news conference will be held at 10:45 a.m. at police headquarters to make the announcement.

“A true son of Chicago who grew up in public housing; went to public schools went on to become one of our most dedicated public servants,” Guglielmi tweeted Thursday morning. “#ChicagoPolice Supt Eddie Johnson will announce plans to retire as leader of the nation’s second largest police department.”

Citing sources, the Tribune reported Tuesday night that Johnson was expected to reveal later in the week that he was stepping down.

His departure comes as city Inspector General Joseph Ferguson’s office continues to investigate an incident into police officers finding Johnson asleep in his car last month. He later told the mayor he had a few drinks earlier that evening.

Instead, Johnson said a recent trip to London to see the Chicago Bears play helped him bring into focus what his family has given up so he could serve as police superintendent.

"I have given 31 years now to this city, and almost four as superintendent," Johnson said. "You know, but I recognize also that at some point it's time to create another chapter in your life. And I will tell you all this: When my family and I went to London for the Bears game, that's the first vacation like that that I've had since I became superintendent. And I looked at my family and it made me realize how much of a sacrifice you make for your family when you take on positions like this."

Johnson said he has been “toying with” retirement “for some time.”

At least two names have been floated as candidates for the interim superintendent position: Former Los Angeles police Chief Charlie Beck and former Illinois State Police Director Leo Schmitz. Schmitz is also a former deputy chief for the Chicago police department.

Ferguson is investigating the Oct. 17 incident in which patrol officers discovered Johnson in his parked car at 12:30 a.m. in Chicago’s Bridgeport neighborhood. The officers allowed Johnson to drive himself to his home. The superintendent has said he felt ill because of problems with his medication, though he also told Mayor Lori Lightfoot he had “a couple of drinks” earlier in the night.

Johnson told reporters Monday he's "not worried" about the investigation.

Johnson also said he wouldn’t have cared about making it to April as superintendent when his pension would become fully vested at the superintendent’s salary.

“Remember, I didn’t apply for this job,” he said. “So that part doesn’t matter to me, it really doesn’t.”

Johnson was hired in spring 2016 by then-Mayor Rahm Emanuel to be superintendent. Johnson took over a department reeling from the court-ordered release of squad car-camera video showing a white Chicago police officer shoot black teen Laquan McDonald 16 times.

During Johnson’s time, the city has seen some reductions in both homicides and shootings, but the Police Department has also struggled to solve crimes, posting abysmal yearly clearance rates.

jgorner@chicagotribune.com