The effort to connect the tracts that now form the Greenbelt into one contiguous park occurred in response to the increasing urbanization of the area, following the opening of the Verrazano-Narrows Bridge in 1964. Woodlands were cleared, and streams, ponds and wetlands were filled as the region's landscape was being permanently altered. A private group of citizens, working to halt the construction of the Richmond Parkway, pressed for the acquisition of all the natural areas in the vicinity. With the establishment of its centerpiece, High Rock Park, in 1965, the formation of the consolidated Greenbelt was well on its way, with its official designation taking place in 1984.

The Greenbelt Conservancy, Inc. is a not-for-profit corporation formed in 1989 to protect and preserve Staten Island's Greenbelt Park. Its continuing legacy is stewardship of the park's priceless, natural areas. In partnership with the City of New York / Parks & Recreation, the Greenbelt Conservancy is dedicated to promoting conservation and preservation of natural areas and increasing public awareness, support, and enjoyment of the Greenbelt. The Conservancy is responsible for the prudent management of its endowment to benefit the Greenbelt.

Greenbelt Park also includes these fine areas: Deer Park, Buck's Hollow, Bloodroot Valley, Reed's Basket Willow Swamp, Egbertville Ravine, and Amundson Trailway.