She had been 746 votes clear of Aaron Hawkins when progress results were released on Tuesday, after about 85% of returned ballots had been counted.
Preliminary results last night showed the race had tightened up with her lead over Mr Hawkins cut to 250.
After the 548 special votes were processed, the final result was release this morning.
Ms Galer (10,201 votes) has been elected, while Mr Hawkins (10,112 votes) finished second and Conrad Stedman was third.
The voter return was 33.31%, being 31,629 voting papers, including special votes.
Nerve-racking wait
Ms Galer said last night the situation was nerve-racking.
‘‘I’m ready to live with whatever result there is,’’ she said.
‘‘If it’s not to be, it’s not to be.
‘‘It’s an uncertain situation.’’
A win for Mr Hawkins still appeared unlikely, but Ms Galer was prepared to consider the possibility.
‘‘I might be the bridesmaid — if that’s the case, I’ll live with it.’’
He could not be reached for comment last night.
A by-election was required to replace Cr Jules Radich, who died in January.
Fourteen candidates stood for the position.
The by-election was run under the single transferable vote (STV) system, which involves voters ranking candidates.
Under STV, the least-favoured candidate drops out one by one and their votes are reallocated in accordance with voter preferences.
When it came down to the final two candidates, preliminary results had Ms Galer on 10,087 votes, ahead of former mayor Mr Hawkins on 9837.
More than 31,000 people voted in the by-election. Voter turnout was sitting at 32.84%.
