Frank Tyas was elected in the Armthorpe ward in last week's by-election which was caused following the death of Councillor Tony Corden.
Mr Tyas took 1,431 votes to hold the seat, ahead of his only challenger, Martin Williams (Independent), the former Thorne ward councillor who had been bidding to return to the council after earlier losing his seat.
Mr Williams picked up 466 votes.
Mr Tyas is also a member of Armthorpe Parish Council and retained the seat won by Coun Corden for Labour in May 2017.