The school ranks in the top 100 schools in the United Kingdom. and is very highly ranked in lists which distinguish clearly between comprehensive and selective schools. GCSE 5 A*-C with English and Maths are usually in the top 3 in the county, A level results are always very high. Johnston achieves the highest results of any state school in the region and has a distinguished track record in getting students from all backgrounds into the most competitive courses. Sutton Trust report 2009 cited it as the only state school in the region reliably to do so year after year. Oxbridge entry is usually between 10–15 each year. The sixth form and its success is the lasting legacy of the longest-serving and most well-known Head, Dr John Dunford (1983–1999).