Former Mayor Rahm Emanuel dumped his first communications director seven months into his administration. Mayor Lori Lightfoot has now done the same in three months.

Marielle Sainvilus abruptly resigned Thursday — nearly two weeks shy of the 100-day mark — amid concern that the new administration was slow to respond to media inquiries and fell short when it came to handling controversies.

Sainvilus is the former director of public affairs for the University of Chicago who joined Lightfoot’s transition team in mid-April, after Lightfoot’s landslide victory and just over a month before her inauguration.

Her resume appeared to make Sainvilus a perfect fit. It included stints as deputy press secretary for the Chicago Public Schools during Rahm Emanuel’s administration, assistant press secretary for the governor’s office and communications director at the Illinois Department of Human Services.

It turned out to be anything but a perfect fit.

In a text message to the Chicago Sun-Times, Sainvilus said she was proud to have led Lightfoot’s communications team “through [most of] her 100 days/couple of months to ensure continuity in the beginning of her administration.”

“It was an honor and a privilege to do so for the first African American woman mayor of Chicago. This was an amazing experience and I look forward to the great things she will accomplish for Chicago,” she wrote.

During a City Hall news conference Thursday to beat the drum for the 22nd annual Chicago Football Classic at Soldier Field, Lightfoot shed no light on the controversy that culminated in the quickie resignation.

“We accepted her resignation. I want to thank her for her incredible contribution — both during the transition and the early part of the administration,” the mayor said.

“We have a great team of people that are here and we carry on.”

The mayor was asked what problems she was attempting to correct by making such an early change.

Did she believe, as others do, that her communications team needs to step up its game in preparation for the tough stuff yet to come, including post-election budget cuts and tax increases to erase a $1 billion-plus shortfall?

“It’s not about that,” the mayor said.

“It’s a learning curve for all of us, right? We’re all new in our various roles. But, I think Marielle did a very good job under difficult circumstances in an administration and a transition that was really, really short and then sourcing talent to help us stand up our shop.”

The mayor was asked, yet again, whether her team needs to be quicker in responding to controversies and general media inquiries.

“Maybe that’s your opinion. But I think we do a very good of making sure that we’re on top of the stories of the day . . . Our folks are working very hard to make sure that we’re being as responsive as possible,” she said.

Political observers were not surprised that the revolving door has spun in record time.

“There was general frustration with turnaround time with media and handling hot topics as they popped up,” said a City Hall observer, who asked to remain anonymous.

“Hopefully, this is a lesson learned for the leadership team as well because they need to be more responsive to and inclusive of the communications team.”

The source noted that Sainvilus was “constantly getting blamed for some of the not-so-great stories that came out and how they were handled. But in reality they were trying to clean up what other people were doing and decisions made about how to roll things out.”

A Lightfoot supporter, who asked to remain anonymous, described communications as a “big early problem” for the mayor that needs to be corrected before the honeymoon ends and the big controversies begin.

An example was the decision to float a long-shot plan to have the state take over Chicago’s $28 billion pension liability, only to be shot down by Gov. J.B. Pritzker.

“Comms was getting out in front of them a lot. She had to clean that up a lot and it cost her,” the supporter said.

A former Emanuel administration official called it a “huge mistake” for Lightfoot to force Sainvilus out before identifying her replacement.

“The team will be rudderless without a leader and that turmoil will only make it harder for the person who takes the job next,” the former Emanuel aide said.

Late Thursday, City Hall announced that Sainvilus will be replaced, starting Monday, by Michael Crowley, who currently serves as chief of staff for After School Matters.

According to the mayor’s office, Crowley has fifteen years of communications experience in the public and private sectors.