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 650 boys in the Lower School and 650 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, an integrated facility for science, technology, art and design together with library and resource centres, a separate Lower School building, and a major new Sports and Conference Centre which was opened in February 2005. A new Performing Arts Centre and a new Sixth Form Centre are currently being completed.