Ald. Maria Hadden (49th) is apologizing to the Chicago Firefighters Union Local 2 for her chief of staff’s “insensitive” Twitter takedown of Ald. Jim Gardiner (45th) that ended up infuriating rank-and-file firefighters.

The intra-mural squabble between freshmen aldermen began when Hadden’s chief of staff Leslie Perkins tweeted a newspaper story about Mayor Lori Lightfoot putting Gardiner in his place.

The mayor had defiantly defended her decision to reward ousted Ald. John Arena (45th) with a $129,996-a-year city planning job over Gardiner’s strenuous objections.

“With due respect to the freshman, I make my decisions based upon the merits. He’s expressed himself. But I’m not gonna have somebody who defeated somebody in an election dictate to me how or when or under what circumstances somebody gets hired,” the mayor said.

“If we start a precedent of somebody who’s a winner basically banning somebody from employment, where does it end? What Gardiner should focus on is what matters to his ward. He doesn’t have a say over my hiring decisions.”

Perkins served as Arena’s chief of staff before making the switch to Hadden after Gardiner, a former Chicago firefighter/EMT, captured nearly 51 percent of the vote to Arena’s 36.2 percent in a four-way field on Feb. 26, avoiding a run-off.

For Perkins, the temptation to get even with Gardiner was apparently irresistible.

She tweeted a story about the mayor’s putdown of Gardiner and wrote, “Everyone that shares this gets to hear the same joke: I wonder how a firefighter feels about getting burned so badly.”

On Tuesday, Hadden acknowledged Perkins’ “joke” was “offensive” to firefighters and never should have been tweeted by her chief of staff.

“She’s sorry. It was a stupid comment. She wasn’t really thinking. We’ve been in communication with Local 2 making sure [they understand]. She’s making a written statement of apology,” Hadden said

“She worked for Ald. Arena. It’s politics. Leftover hard feelings with the election results. Sometimes, people let their emotions get the best of them . . . She wasn’t trying to put down the firefighters. It was an insult aimed at Gardiner. Their personal, leftover things from their dealings in the 45th Ward.”

Perkins could not be reached for comment.

The chaplain emeritus of the Chicago Fire Department, the Rev. Thomas Mulcrone, was so incensed by the tweet that he fired off a letter to Hadden warning that her “standing with members of the CFD [and] dare I say first-responders will be non-existent” if she doesn’t “address this matter with serious consequences” for Perkins.

“Have you any idea of the pain and suffering that firefighters go through when they are burned? Do you know that the scars — both physical and emotional — remain with them the rest of their lives,” Mulcrone wrote.

Mulcrone noted he has spent countless hours in the waiting rooms of hospital burn units comforting firefighter families whose loved ones are “wrapped in surgical gauze and unable to communicate.”

“This is a very real fear that CFD firefighters and their families live with every day. That your employee, Ms. Perkins, would joke about something like this is horrific and repugnant,” Mulcrone wrote.

Hadden said she’s well aware of how insensitive the tweet was, but she has “handled it internally” in a way that allows Perkins to keep her $70,000-a-year job.

“I appreciate the upset that this has caused. I’ve made personal apologies and personal statements. She’s making one as well. We’re working this out internally,” the alderman said.

“People make mistakes. They say stupid things on social media. People need to learn from it. [But] people aren’t disposable. This doesn’t rise to the level of firing somebody.”

Gardiner refused to pass judgment on Hadden’s handling of Perkins’ tweet. He would only say, “I hope she has learned her lesson. It was a very reckless comment that she made.”

As for the lingering animosity, Gardiner said it’s obvious Perkins is “vindictive towards me due to the fact that I beat John Arena so badly” in February.

“She’s made several comments on social media stating that she hopes that I lose the next election and she hopes certain parts of my ward get remapped out of my ward,” he said.