MONMOUTHSHIRE council's planning committee unanimously gave permission for a new supermarket in Caldicot.
The Asda store will be built on four acres of Caldicot Comprehensive School's playing fields and will be located at least 25 metres away from it.
Councillors first gave their permission for the supermarket in April 2012.
Now the full scheme, with pedestrian links and a new relief road which runs around the perimeter of the store to take traffic away from Woodstock Way, has been accepted.
As part of the plan, officers said it is "vitally important" for clear links between Caldicot's town centre and the store to be established.
Pedestrian links between the two "will be enhanced" and the area further developed.
As part of the plan being accepted, more than £600,000 will be spent on improvements in the town.
Cllr Jim Higginson, who represents Caldicot on its town council and on the county council, supported the plan.
He told the committee: "We do need it. There's a hugely significant leakage in in-town spending going elsewhere. That's not good for the business there.
"Everyone is waiting for the development. It's widely accepted by the people in Caldicot. It's about time something was done there."
Caldicot Town Council said they gave their approval to the plan, while Magor and Undy community council said “serious consideration” was necessary for trees adjacent to Chepstow Road.
Monmouthshire County Council’s biodiversity group was satisfied the site’s impact was limited to only nesting birds.