Businessman Damon Odey is Timaru's new mayor, while Claire Barlow has won a second term leading the Mackenzie District.
Mr Odey replaces Janie Annear, who did not seek re-election, his 10,335 votes nearly double that of rival Steve Earnshaw.
He said his focus as mayor would be to build on the positive growth in the region.
"Timaru's in a pretty good position at the moment so it's just getting the new elected members up to speed and carrying on with business as usual, having a good discussion with them all and just seeing what their plans and thoughts are and making sure we can all work together."
Ms Barlow's 1202 votes were also about double the number for challenger councillor Graeme Page, and she said she was humbled to have been re-elected.
Setting a strategic vision would be among the council's first priorities, and that would mean working as a council to find out what the goals were for the next three years.
"Then I'll be encouraging any new members to have elected member training, so they know what their roles are, and then I'll be just looking forward to getting down to work and another three years in the job," Ms Barlow said.