The agreement will see a 34 hectare park with three lakes created, paid for by building and selling homes in a lakeside village.
Construction and building materials group Brett has already restored the land from its former use as a gravel works. It is currently in negotiations with housebuilders to deliver this aspect of the project.
The park, called Conningbrook Lakes, will be managed by a partnership involving the council, Ashford Leisure Trust, Kent Wildlife Trust and Mid Kent Fisheries, with the public able to access the park and take part in water-based activities through a number of specialist clubs and associations.
Portfolio holder for parks and open spaces councillor Jessamy Blanford said: "With a beautiful lakeside setting, views to the North Downs and access to a network of country trails, Conningbrook Lakes will be a family-friendly facility for visitors to explore and enjoy.
"This park will be another stunning attraction for Ashford, and reinforces the borough’s reputation as a great place to live, work and relax."
Brett Group chairman Bill Brett welcomed the first stages of the project. "We are delighted that the long-held vision of a country park which we have worked on for so long with Ashford Borough Council is now about to be realised," he said. "It promises to be a great asset to the community."
Conningbrook’s setting will also provide a gateway attraction for walkers and cyclists to explore the Stour Valley, and to extend and enhance riverside wildlife habitats.