She said she feels privileged to have had "very strong" support from the voting public in Wellington City but will "have to leave regional council prior to the 2016 election".
"I want to make any gap in my constituency as short a time as possible," she said. "However, I have made it clear to colleagues on the authority that I will not make any decisions on local government, even if they do not apply to me, while I am still on the regional council."
South Wairarapa mayor Adrienne Staples said, "Fran has tremendous experience in local government and state services-type situations because of her career.
"She will bring that experience to the role."
Mrs Staples said she had been initially concerned over the pecuniary conflict of interest but "if she's stepping down as councillor then there's no conflict".
Carterton mayor John Booth said there had been a few comments "being made around the traps" that having lost the chair [of Greater Wellington] Ms Wilde would be looking at different options in her life.
"If you put the governance thing to one side, there have been a lot things that have been done in Wairarapa with Fran as chair that have moved things along over here," he said.
As a property owner in Morison's Bush, she was "in a position to see things", he said.
"She has her heart over here in Wairarapa."
Wairarapa Chamber of Commerce chief executive Stephanie Gundersen-Reid said Ms Wilde loved Wairarapa and always had its best intentions at heart. "I believe she's done a great job on the regional council, and I wish her all the best for her future."
Ms Wilde was the champion for the Local Government Commission's proposal to amalgamate the nine Wellington councils, and the regional council, under a one-council "super-city" banner.
But Ms Wilde struggled to convince Wairarapa councils and the Wairarapa public to support joining up with Wellington, Hutt City, Upper Hutt, Porirua and Kapiti.
The proposal ran into heavy opposition across the region, and in June the commission abandoned the proposal following public submissions which showed 89 per cent were against a super-city.
Soon after, Ms Wilde quit as chairwoman after nine councillors signed a letter of no confidence in her.