The partners will bring forward up to 1.55m sq ft of commercial space on over 100 acres at Stanton Cross.
The £900m development has outline consent for a mix of commercial uses including industrial and distribution, offices, retail and leisure.
The broader development being delivered by Bovis Homes will be the largest growth Wellingborough has seen since the 1960s and will include 3,650 homes.
Work on new infrastructure to serve Stanton Cross is already underway, including two new roads and two new bridges across the Midland Mainline and River Ise, as well as improvements to Wellingborough Railway Station by Network Rail.
The first residential phase for 379 homes received detailed planning consent last October and is due to start on site this year.
Rupert Wood, regional director for the Northern Home Counties at St Modwen said: “It is a major project for our growing Northern Home Counties region and will provide a significant development pipeline in an area which is seeing economic growth.”
Stanton Cross will take around 15 years to complete.