Labour's Alan Billings has been voted in as the new Police and Crime Commissioner for South Yorkshire.
Dr Billings took just over 50% of the vote in the poll held following the resignation of Shaun Wright following the Rotherham child abuse scandal.
UKIP's Jack Clarkson finished second with 32% of the vote, the Conservatives were third and the English Democrats fourth.
The turnout was 14.88%, down from 14.93% in 2012.
Doncaster council chief executive, Jo Miller, said the turnout at the ballot box in the town was only 3.5%, with 11.7% postal votes.
Dr Billings said: "I'm very pleased. It's been very, very hard fought. Given the circumstances it's very gratifying that the Labour Party is able to re-establish itself in South Yorkshire as a credible force."
The Conservative candidate Ian Walker took nearly 13% of the vote, with David Allen of the English Democrats polling just under 6%.
The by-election was called after Mr Wright resigned on 16 September following weeks of pressure over a report into child abuse in Rotherham.
He said he took the action "for the sake of those victims, for the sake of the public of South Yorkshire and to ensure that the important issues outlined in the report about tackling child sexual exploitation can be discussed and considered in full and without distraction".
The Alexis Jay Report revealed that more than 1,400 children in the town had been sexually exploited by gangs of men.
Mr Wright had been the councillor who oversaw Rotherham's children's services between 2005 and 2010.