Sheila Powell has been voted in to represent Mid-Formartine, which covers towns and villages including Balmedie, Belhelvie, Pitmedden and Oldmeldrum following a by-election this week.
The Conservative replaces former SNP councillor Karen Adam, who resigned in May after being elected as an MSP for Banffshire and Buchan.
Her election means the council will return to a full complement with 70 elected members.
Votes were counted electronically at Inverurie Town Hall on Friday morning.
Ms Powell said she was delighted to have won, and will join fellow councillors Jim Gifford, Paul Johnston and Andrew Hassan to represent the area.
A total of 3,257 votes were cast by constituents, meaning there was a turnout of just under 28% at the by-election.
Results: Ms Powell, Con, 1,480; Jenny Nicol, SNP, 1,205; Jeff Goodhall, Lib Dems, 412; Peter Kennedy, Greens, 144.