In a last-minute shocker, Liz Breadon was elected president of the Boston City Council on Monday, defeating Brian Worrell, who appeared to have the votes the night before, after another councilor who claimed to have the job for months dropped out.

Breadon was elected, 7-6, to lead the body at the first meeting of the year, ending an unusually public process for what is typically an exercise marked by internal, behind-the-scenes negotiations that do not play out in the public eye.

Breadon, a fourth-term councilor who represents Allston/Brighton for District 9, was nominated by Councilor Benjamin Weber, seemingly after last-minute backroom negotiations and maneuvering upended Worrell’s reach for the presidency, which appeared to be firmly within his grasp after Gabriela Coletta Zapata announced Sunday night that she was no longer seeking the position.

“It’s incredibly humbling for me to be here,” Breadon said. “I didn’t know I would be standing here this time yesterday, but that said, I am ready to lead. I feel that I bring a certain mindset to this job … I will continue to be a peacemaker, a bridge-builder, and someone who hopefully will be instrumental in helping us move forward positively.”

Breadon, the first openly-gay woman to be elected to the City Council, was not believed to be actively seeking the position in recent weeks.

Worrell was nominated by Councilor Ed Flynn, who praised his work leading the Council’s budget process as chair of the Ways and Means committee last term and said he would have had an open-door policy to listen to his colleagues should he have been elected to lead the body.

Coletta Zapata, an ally of Mayor Michelle Wu, claimed on Nov. 10 that she had the secured the necessary seven votes from her colleagues to be elected president, but withdrew her name from consideration amid political chatter that three councilors had flipped their votes from her to Worrell.

Breadon was said to be one of the three councilors to flip their votes to Worrell, according to two City Hall sources, along with John FitzGerald and Enrique Pepén.

The three councilors defected due to their concerns over Coletta Zapata’s decision to name Henry Santana, a Wu ally who needed support from the mayor’s campaign to make the September preliminary ballot, as vice president, per City Hall sources.

Coletta Zapata is pregnant, meaning that Santana may have led the body at times in her potential maternity leave absence, should she have been elected president.

On Sunday night, Pepén was also being floated as a potential challenger to Worrell after Coletta Zapata dropped out in a bid that a City Hall source said was backed by the mayor’s office.

Pepén cast his final vote for Breadon, who will succeed Ruthzee Louijeune, who was barred from seeking the presidency again due to term limits. FitzGerald voted for Worrell.

The Council president sets committee assignments for the body, leads Council meetings, and perhaps most importantly, serves as acting mayor in the mayor’s absence.

The last-minute shocker led to speculation from some councilors that Wu had a hand in the Council president election process. Breadon was nominated by Weber, an ally of the mayor, and was backed by her other allies, including Sharon Durkan, who spoke in support of her candidacy on the Council floor before the vote.

Councilor Julia Mejia, who launched her own bid for Council president largely in an attempt to “disrupt” the backroom negotiations that often define the internal vote, criticized her Wu-aligned colleagues for the last-minute attempt to thwart Worrell’s bid for the presidency — by accusing them of maneuvering in such a way to cling to power that they may have seen as slipping away.

“There have been a lot of shenanigans happening over the last two-and-a-half months as it relates to this particular race, and I think that all eyes are on us to demonstrate that we are independent and that we can make decisions for ourselves, and that we don’t have people behind the scenes dictating who is going to be our leader,” Mejia said before the vote.

Weber, in nominating Breadon, who he described as someone who could be a calm and steady voice in “tempestuous” times, also criticized the internal voting process, particularly as it played out in the last 24 hours leading up to the vote — which featured councilors shifting their commitments from Coletta Zapata to Worrell to ultimately Breadon.

“I think the last 24 hours,” Weber said, “have not been the finest of this Council.”