The Labour Party has kept its seat in a ward where "antisocial behaviour and litter" were the main issues for voters.
Robert Thompson held one of the Kilburn seats with 583 votes following a by-election on September 5.
Peter Hornsy for the Local Conservative Party came second with 253 votes.
Michael Gomes Vieira, standing for the Green Party, came third with 198 votes and Liberal Democrat David Elkin polling 98.
Lloyd Hatton resigned his Kilburn seat after winning the South Dorset seat in the July 4 general election.
The turnout in Kilburn was only 13.10%, with postal vote turnout 35%.
By-elections were also held in Kentish Town South and Camden Square.
Cllr Thompson said: "I feel really grateful to have the confidence of the people in Kilburn.
"I'm a local person and really aware of the challenges. I look forward to working with residents on their issues."
He said the biggest issue on the doorstep was anti-social behaviour and litter. "Kilburn High Road is a bit of a mess, after that was housing" he added.
"When I was a councillor in Kensington and Chelsea before housing was the biggest issue. I think Camden is much better at looking after its housing stock."
Peter Hornsby said he was "disappointed by the turnout".
"It reflects that people in Kilburn feel left behind and taken for granted,
"We have a long way to go for the Conservatives to regain the trust of the community but I'm proud of the process engaging with residents.
"We are grateful for the support and hope to win more support next time."
Two other by-elections took place on Thursday in Kentish Town South, won by Labour's Joseph Ball and Camden Square, won by Tricia Leman, also Labour.
Camden Council leader Richard Olszewski said he would have liked to have seen a higher turnout.
"We have had a lot of politics. We're coming on the back of a huge general election campaign and it is a feature of by-elections that turnouts are lower and we had terrible weather on polling day," he said.
"Nevertheless, despite the low turnout the Labour majorities were a strong endorsement of each of the candidates personally and of the Labour council."
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