St John’s School was founded in 1851 by the Reverend Ashby Haslewood, vicar of St Mark’s, Hamilton Terrace, north London. He had a dual purpose in founding the School: to offer free education for the sons of poor clergymen and to provide a choir for his large church.

The first headmaster was the Reverend Anthony Thomson (headmaster 1852-1857), curate of St Mark’s and the first eight boys, known as ‘Foundationers’, joined the School in January 1852. 
 

The School moved to Greville Mount House, Kilburn and the name St John’s was adopted. This was the first of three moves before the School moved to Leatherhead in 1872.

The School was temporarily transferred to the Reverend Lewis P Mercier’s (headmaster 1857–1861) school at Walthamstow. 

Clapton House, a large mansion house in east London was leased.

50 boys in the School.

Edwards Hawkins became headmaster (headmaster 1861-1883)

Twelve acres of land acquired in Leatherhead for a new purpose-built school at a cost of £2,500. An appeal was launched to raise a further £12,490 for the building fund.

Building works commenced on the Epsom Road site.

The School moved to Leatherhead with 70 boys.

Foundation stone laid for the School Chapel.

Chapel dedicated by the Bishop of Winchester.

100 boys in the School.

The two-storey building, next to the Dining Hall was built in 1881 as the School Infirmary.

135 boys in the School.

Arthur Rutty became headmaster (1883 – 1909)

The first gymnasium was opened on 21 March 1891.
Every form in the School had two 45 minute lessons a week.
The instructor was Sergeant Whelan. 

209 boys in the School.

The School continued to expand and two boarding houses, known as Block A and Block B, were constructed in 1891 and 1894.

280 boys in the School.

New Dining Hall opened.

246 boys in the School.

The first cricket pavilion cost £360. It was designed to look like a Swiss chalet with a red tile top, verandah, tea room and changing rooms.

264 boys in the School.

New fives courts were built in 1908 in memory of Charles Churchill, founder of the School.

Edmund Downes became headmaster (1909-1932)

On 9 June 1913 a serious fire destroyed the main school building.
Dormitories, classrooms, assistant Masters’ rooms, the matrons’ room, the large schoolroom and the library were completely destroyed.
Roofs and ceilings fell in and the wooden floors were burned beyond recognition.

The School was rebuilt and officially opened on Speech Day 1914 by HRH the Duchess of Albany.

265 boys in the School.

768 old boys fought in the Great War.

The War Memorial was dedicated in 1920 in memory of the 162 Old Johnians who died.

255 boys in the School.

As a further memorial to the Old Johnians who were killed in the First World War, a swimming pool was built next to the fives courts on the Senior Field.

250 boys in the School.

Jack Carter became headmaster (1933-1947)

A new building with 14 classrooms, three laboratories and two lecture theatres, was opened on the site of the old kitchen garden.

The Right Honourable Lord Ebbisham, GBE, opened the new cricket pavilion on 20 June 1936.

Hereward Wake became headmaster (1948-1960)

A new gymnasium was built to take the place of a former building damaged by the blast from a land mine in the Second World War. Field Marshal the Viscount Montgomery of Alamein formally opened the building with a golden key.

348 boys in the School.

Ian Sutherland became headmaster (1960-1970)

The School Chapel was constructed in 1962 thanks to an anonymous benefactor. Viscount Montgomery of Alamein, Chairman of the Governing Council, persuaded a friend to provide the money (£50,000). The Chapel was dedicated by the Bishop of Guildford, the Right Revd George Reindorp, at a service on Speech Day, 13 June 1963.

341 boys in the School.

In 2010 it was revealed that the anonymous donor was Garfield Weston of the Garfield Weston Foundation.

Edward Hartwell became headmaster (1970-1985)

By 1973 the number of boys in the School had grown and a new day house was needed. It was named Montgomery House after Field Marshal Montgomery, Chairman of the Governors, 1950 – 1966. Space for Montgomery House was created by splitting the former Block A (North House) into two, so that Monty occupied one side of the building and North the other side.

396 boys in the School.

David Brown became headmaster (1985-1992)

Girls admitted to Sixth Form for the first time. Hallaton House in Garlands Road refurbished as accommodation for girls.

466 pupils in the School.

Construction on a sports centre next to the swimming pool started in 1989 and the building was opened on 17 October 1991 by HRH the Duchess of Gloucester.

Christopher Tongue became headmaster (1993-2004)

A new building was superimposed on the front of the original 1936 classroom block, providing new teaching accommodation, a Sixth Form Study Centre and Multi-Media Studio.

The new Performing Arts Centre is built on the site of the former gymnasium and theatre. The building was opened by the Duchess of Gloucester in 2003.

448 pupils in the School.

Nicholas Haddock became headmaster (2004-2011)

The Henry Dawes Centre opened in September 2010, providing St John’s with state-of-the-art teaching space, a new library and specialist facilities for design technology, art and graphic design.

Girls joined the Fourth Form in 2010 as the School became fully co-educational.

540 pupils in the School.

Martin Collier became headmaster (2011-2017)

Churchill House moved into a new building and became a day house.

652 pupils in the School.

The former Churchill House building was refurbished and re-opened in 2013 as a boarding house for girls. It was named Gloucester House after our Patron, HRH the Duchess of Gloucester.

660 pupils in the School.

Originally built in 1876, the Old Chapel was refurbished in 2014 to create a venue which is used by St John’s and the local community.

660 pupils in the School.

This high-tech and high-spec building provides the School with eight new science labs for chemistry and biology. It was officially opened on 25 May 2016 by Field Marshal Montgomery’s granddaughter, Lady Arabella Stuart-Smith.

In September 2016 the School opened its doors to Year 7 pupils for the first time, with a brand new Lower School for 11+ entry.

717 pupils in the School.

Rowena Cole became The Head of St John's.

Work has commenced on the new indoor sports facilities. These will replace the former swimming pool with a new competition-standard six lane, 25m pool.

803 pupils in the School.

The new sports centre opened in Autumn 2019 housing swimming pool, sports hall, fitness suite and studio. 

September 2019 also saw a new girls' day house - Hawkins House - opened. Hawkins was named after Reverend Edwards C Hawkins, headmaster from 1861 to 1883, who moved the School to Leatherhead.

833 pupils in the School.