Millions went to the polls on Saturday to elect 46 councils and, while final results are almost a week away, many mayors have already taken to social media to claim victory.
Mr Ruddock, Australia's second-longest serving federal politician, came out of retirement on a Liberal ticket to snatch the mayorship of Hornsby by a convincing margin.
He secured 48.44 per cent of the vote with all the formal votes counted on Saturday evening, eclipsing the second-placed candidate by almost three times as many votes.
"I've come back into (politics) with a very clear focus," Mr Ruddock told AAP.
"I often make the point we are the city's lungs. You need to maintain them."
In Newcastle, Labor candidate Nuatali Nelmes was re-elected with 43.86 per cent by the time all formal votes were counted.
The race tightened in Wollongong, however, with Gordon Bradbery leading David Brown by only a few thousand votes. It was still too close to call on Saturday night.
The Greens said they had a strong increase in support and may win between 29 and 34 positions across the state.
"NSW has seen through the ugly politics of forced amalgamations, privatisation and overdevelopment being pushed by the Liberal government and demanded change," NSW Greens MP David Mr Shoebridge said in a statement.
About 2.8 million people were enrolled to vote in the 46 council areas which went to the polls, the first council elections since the state government walked away from its controversial amalgamations plan.
Final results are expected by September 16.
