John G. McCarthy was a wealthy American who lived after retirement for part of each year in Sussex.
He met William Mount, chief landscape architect at East Sussex County Council, in the late-1970s, and a mutual concern over the fate of historic gardens and landscapes in the county led them to set up the Historic Gardens Trust (Sussex) in 1980.
Over the next decade, the Trust was instrumental in the restoration of many landscapes, including Brightling Park and the Royal Pavilion, Brighton. Most of the work was privately financed by John McCarthy and other benefactors introduced by him.