The battle for mayor on the new 15-seat council was a showdown between Cr Byrne, a former mayor of Leichhardt, and first time councillor Pauline Lockie.

Cr Byrne secured a majority of eight votes after the five Labor councillors brokered a deal with two Liberals councillors and independent Victor Macri.

Cr Byrne was met with solid applause from the packed council chamber as his victory was declared. However, it was punctuated with heckling from members of the public who accused him of "doing a deal with the devil. "

The Liberals - a minority faction with just two seats on the Labor and Greens dominated council - were rewarded with the deputy mayoral position, after Labor threw their numbers behind Liberal councillor Julie Passas' bid for the role.

The deal outmanoeuvred the Greens, who were left without a leadership position on council, despite holding five seats, the same number as Labor.

In his acceptance speech, Cr Byrne promised to "lead a council which is both progressive and effective," declaring "tonight democracy returns to the Inner West."

"With our belief in social justice and our commitment to diversity, we can show the rest of the country how progressive principles can be put into practice at the local government level," he said.

The appointment of a democratically elected mayor to the council's helm concludes a 16-month period of administration, following the merger of Marrickville, Leichhardt and Ashfield councils in May 2016.

Cr Byrne had been transparently ambitious about his desire for mayoralty, announcing his candidacy for the top job during the election campaign.

Cr Lockie, an independent who garnered a community profile as an anti-WestConnex campaigner, had the added challenge of convincing her new colleagues her inexperience shouldn't disqualify her for the job.

She said her tilt for mayor was a late decision, after learning of the deal worked over between Labor and the Liberals, which she described as "not reflective of what the community wants."

Her bid won the support of five greens councillors, who had refused to negoitate direcrly with the two Liberal councillors, and an independent John Stamolis, but fell one vote shy of the majority needed.

On Thursday afternoon, just hours from the mayoral vote, the numbers were still in play.

The Greens were concerned that, despite having five seats on council, they would be blocked from the leadership positions through a power-sharing deal between Labor and the Liberal.

After their fears were confirmed on Thursday night, Greens councillor Colin Hesse said his team was "deeply disappointed."

"It appears Labor has put their electoral interests above the community interests. We feel tonight's deal with the Liberals augurs poorly for campaigns against WestConnex and the metro rail," Cr Hesse said.

As the more conservative of the three independents, Victor Macri, a former mayor of Marrickville, entered the meeting as a potential kingmaker.

He said his phone had been ringing all day, as councillors tried to wrangle their numbers and cut deals in exchange for his support.

Cr Macri, however, refused to reveal his hand before the meeting, stating his intention to enter the council chamber "with an open mind and see what's on offer".

However, he said he would only back "an experienced candidate", effectively ruling out any support for newcomer Pauline Lockie.

For their part, the Greens said they put their own deal on the table, offering to support Cr Byrne as mayor for the first two years while serving as his deputy, in exchange for the Greens occupying the mayoralty in the third and final year.

"We are really keen to get that progressive council," Cr Hesse said. "If that means us not being mayor, we're ok with that."

But Cr Byrne said no such deal was every offered by the Greens.