Last Thursday’s by-election saw the 27-year-old beat former mayor Tim Davies and another former independent councillor James Plastow.
Coun Brennan, of Richardson Rise, Gainsborough, leapt to victory with 296 votes, 58 per cent of the votes cast.
Tim Davies was second with 118 votes (23 per cent) and James Plastow came third with 97 votes (19 per cent).
Coun Brennan said he was ‘ecstatic’ to have been voted onto the council.
“I would like to thank the people across Uphills Gainsborough who voted for me,” he said.
“I was pleased that those who voted clearly preferred a new candidate.”
He said GAPA was a cause close to his heart, and he would push for more funding for the facility.
“I live in the ward and will campaign on the issues that matter within the ward,” he said.
Coun Brennan asked anyone with a local issue in the East ward to contact him on 07528 271696 or [email protected]