Julie Wirth has been finance director at Musgrave, which runs rival convenience store chains Budgens and Londis, since 2008.
But she will move to Conviviality, which also runs the Select Convenience and Thorougoods chains, on November 4.
The appointment comes days after the business was floated on the Alternative Investment Market, raising £65 million.
Chief executive Diana Hunter now plans to open more than 60 new stores by 2016, mainly in the south east and Yorkshire, and can now count on the support of a chief financial officer with 25 years’ retail experience.
Wirth trained as an accountant before embarking on a 20-year career at Argos and Homebase owner Home Retail Group, where she worked her way up to director of group finance.
Hunter said: “I am delighted to welcome to Conviviality a finance director of the calibre and experience of Julie.
“She has worked in businesses that utilise the same model so understands fully the axis between the company and its partners, the franchisees.”
Wirth added: “I look forward to joining Diana and the team and see Conviviality as a terrific opportunity to join a business with strong brands, the appropriate capital structure and a robust platform for growth.”