A new B&M store planned for the old Focus site on Rockingham Road will bring £1milllion a year in wages to the town, its bosses claim.
The store will create at least 70 new jobs, paying staff a total of just over £1m a year.
The Rockingham Road outlet will concentrate on low-priced DIY and home goods, and will also feature a garden centre.
The new store should open in spring next year, after a £500,000 refit.
The former Focus site, originally built in 1980, had been vacant for almost four years.
Tesco had controversial plans to build a new supermarket on the site, which was approved by the council despite local protests.
Then Tesco dropped the scheme after cutbacks nationally.
Now the rapidly-growing B&M Retail Ltd has confirmed its plans to open one of its homestores there.
The group already has a smaller branch in the town centre, and has expanded from 21 stores to more than 400 in just 10 years.
In a report to the council, an agent acting for B&M said: “We forecast that a minimum 70 jobs will be created by the proposal.”
A B&M spokesperson added this week: “We’re feeling really positive about the creation of new jobs for local people and we hope customers are going to be delighted with their new store.”
The project is supported by the Market Harborough Civic Society.
But the society said they would like to see a pedestrian crossing on Rockingham Road, buses to the site and improved access roads.