Just a year ago, Mayor Bloomberg sarcastically praised Council Member Eva Moskowitz for “going back to grandstanding on education” rather than intervening in a dispute over sidewalk cafes. Two years ago, the mayor derided the Upper East Side Democrat as a “gadfly” for holding hearings on the teachers contract.

Yesterday the mayor was all smiles as he accepted Ms. Moskowitz’s backing for his re-election effort.

“I’m thrilled to have your endorsement,” Mr. Bloomberg told the chairwoman of the City Council’s Committee on Education. “I have committed every economic and political resource I have to the goal of giving all of our students the education they need and they deserve. I know I’m standing beside someone who agrees wholeheartedly with that goal.”

The mayor briefly discussed the highlights of his education record before giving Ms. Moskowitz a warm kiss on the check and heading to City Hall.

Ms. Moskowitz has held more than 100 hearings since January 2002, often grilling the schools chancellor, Joel Klein, and other Department of Education officials about everything from the education budget and school safety to the status of schools’ toilet paper supplies and the state of social studies education. Some of the battles have turned nasty.

Three years ago, Ms. Moskowitz complained that City Hall was blocking her from talking to principals and teachers. The mayor’s spokesman, Ed Skyler, was quoted as saying, “I don’t waste my time responding to wastes of time.”

Two years ago, Ms. Moskowitz held a series of hearings on the teachers contract, prompting Mr. Bloomberg to call her a “gadfly” – a persistent, irritating critic; a nuisance.

Last fall, Ms. Moskowitz bypassed the chancellor and the United Federation of Teachers and sent an open letter to the mayor urging him not to give in to the teachers in contract negotiations. Mr. Bloomberg accused her of “grandstanding.”

At about the same time, Ms. Moskowitz held a hearing about toilet paper, after which she said denying it to children could be a “violation of the Geneva Convention.”

Mr. Bloomberg responded that someone should “flush” Ms. Moskowitz and other critics “down the toilet.” Last spring, Ms. Moskowitz issued a subpoena to compel the education department to testify about its implementation of a new anti-bullying law the council passed over the mayor’s veto.

Again, the Bloomberg administration accused Ms. Moskowitz of “grandstanding.” She even criticized the politicization of the school system under the newly centralized Department of Education, which Mr. Bloomberg created when he won mayoral control from Albany.

Yesterday afternoon Ms. Moskowitz did not deny that she had clashed with the administration, but she said Mr. Bloomberg is the best man for the top job. “I have at times been critical of the Department of Education for not always serving parents and kids as well as it could, and I will continue to look out for the interests of parents and children,” she said. “But I have always called it as I have seen it, and today I believe that Mike Bloomberg is the best candidate for mayor, and I have called it as I’ve seen it.”

Ms. Moskowitz praised Mr. Bloomberg for putting “educational reform front and center.” She also commended him for refocusing the schools on “teaching and learning,” and for having “embraced innovation” in the form of charter schools.

Ms. Moskowitz didn’t endorse a candidate during the Democratic primary.