He and his wife, marketing and branding consultant Sarah Eliott, have bought Olssen's Wines, at Bannockburn, and took over on Monday.
Neither has run a winery, but Mr Weldon said from Bannockburn yesterday they were "very comfortable" about their decision.
"The quality of the wine is already world-class and the wine maker is world-class, too. What Sarah and I will be able to add is our business skills."
Winemaker Jen Parr would remain on the staff, he said.
"She's very committed and talented ... we'll be keeping her".
Mr Weldon said he and Ms Eliott would not live in Central Otago permanently but planned to spend "a very significant portion of time" there.
Olssens was the first winery in the Bannockburn area when former owners Heather McPherson and John Olssen established vines 22 years ago.
Ms McPherson said yesterday she had "mixed feelings" about the sale.
"Twenty-two years is a long time ... It is nice to get some fresh blood and energy here."
She said she would stay on with Mr Weldon and Ms Eliott for a time, but did not know yet what her role would be, whether she would work full-time or part-time or how long she might remain on staff. She would continue to live in Bannockburn.
Mr Weldon last week announced his resignation as chief executive of NZX, the operator of the stock exchange, and said he would leave early next year.
That was still his intention, he said yesterday.
The timing of his resignation and the purchase of Olssens was coincidental, he said.
He and Ms Eliott had been looking across the country for a winery for the past two years.
Bannockburn and the potential of its pinot noirs had always appealed, he said.
"It is a great part of the world, and a great opportunity for us."
