The School was founded in 1596 by John Whitgift, Elizabeth I's last Archbishop of Canterbury, and opened in 1600, making it Croydon's oldest school; the present Headmaster, Dr Christopher Barnett, is the twenty-sixth in the School's history. There are approximately 600 boys in the Lower School and 600 boys in the Upper School. Haling Park, to which the School moved in 1931, was at one time the home of Lord Howard of Effingham, Lord High Admiral of the Fleet sent against the Armada, and it retains the appearance of an attractive country estate..

The original buildings have been supplemented by many additions and improvements including an outstanding Music School and Concert Hall, a separate Lower School building and a major new sports complex which was opened in February 2005. In 1990, one of the largest and most innovative educational building projects in Britain was completed to provide an integrated facility for science, technology, art and design together with library and resource centres of exceptional quality.