Mr Stewart, who applied for the managership of the Mega store and secured it after interviews, said he was looking forward to the challenge. A roll-out of what customers could expect on opening day would form part of next week's press release, he said.
The Mega store is owned and will be run by Masterton's Rex Slight and his son-in-law Ivan Frederiksen, with Mr Slight's son and former World Superbike star Aaron Slight having a shareholding in the company.
It covers 8000sq m and will carry 30,000 stock lines.
Included will be a 1000sq m garden centre, a children's play area, a trades sales area, the retail store, 200 car parks, offices and a cafe.
The store's owners have confirmed the business will continue to sponsor the Life Flight Trust helicopter, Masterton's Kids Own playground and the town's Christmas parade.