Now-former city Investigations Commissioner Mark Peters seems to be something of a jerk. This doesn’t make him wrong about Mayor Bill de Blasio.

Peters has been chewing on Kaiser Wilhelm’s leg for years now, and it is totally understandable that the mayor would want him gone. And gone is what he is, effective Wednesday.

“This is an individual who did some very inappropriate things,” said de Blasio. “I am exercising my authority under the [City] Charter to make sure there’s a change in that office.”

The mayor’s got a point about Peters’ conduct during his five-year tenure. Once upon a time he handled a whistleblower unkindly. He’s pushy. He’s a power-grabber — and he had no apparent respect for the natural boundaries of his office. (Much like Hizzoner himself, it might be said.)

But how could de Blasio not have known this going in? The two were Park Slope neighbors; they served together on Community School Board 15 way back in the day; their paths regularly crossed politically — and they were so tight that the mayor tabbed Peters to chair his campaign-finance operation in 2013.

Indeed, there was considerable concern when the mayor-elect hired his money-man to run the investigations office. And New Yorkers who expect the worst of their elected leaders rarely are wrong.

But then something strange happened — a man of cantankerous integrity emerged and set about doing the job he believed he had been hired to do: That is, cast a gimlet eye on the workings of one of the largest, most intricately balanced — and corruption-prone — governments in the world.

In stark contrast, de Blasio quickly undertook to play shady, what’s-in-it-for-me New York politics — while also attempting to elevate his mayoralty, and his more-progressive-than-thou self, to national prominence.

Instead, he attracted the attention of state and federal criminal investigators, escaping indictment only by the narrowest of margins and running up millions in legal bills — most of which have been or will be passed along to the taxpayers for settlement.

So at the very least, de Blasio has no standing to cluck his tongue when Mark Peters’ name is mentioned.

Indeed, one of the first de Blasio-Peters collisions was over a highly pungent transfer of title to a Lower East Side nursing home that — mirabile dictu! — swiftly was converted to luxury condos. Peters was on that special-interest bonanza like flies on cow flop, earning de Blasio’s bitter enmity along the way.

This set a pattern, to put it mildly. Peters went after the bizarre conduct of de Blasio’s hand-picked jails commissioner — the fellow who disappeared for days at a time while running up city-paid travel bills. Peters dug deeply into the Administration for Children’s Services, enraging the mayor.

And he targeted de Blasio’s hugely flawed stewardship of the Housing Authority, causing City Hall much embarrassment — and, The Post reported at the time, prompting the mayor’s decision to dismiss his investigations commissioner.

It was a bumpy ride for all concerned. Especially Peters.

In a 10-page letter responding to his dismissal, the ex-gumshoe on Monday described what he termed a series of attempts by City Hall to deep-six investigative reports:

“These incidents demonstrate a pattern in which the mayor and his senior staff believe that I owe a duty of loyalty to the mayor rather than to the city as a whole and that my actions, in exposing waste, fraud or abuse in city agencies . . . are improper and justify retribution.”

De Blasio denies all that, as one might expect.

But two points are worth noting here:

At least this can be said of Mark Peters: He got out with his reputation bruised but intact. Bill de Blasio should be so lucky.

Bob McManus is a contributing editor at the Manhattan Institute’s City Journal.