The first school on the site opened in 1868 and was known as the 'Upper Harbour West School' and had 21 pupils.
The building consisted of a classroom and two small rooms used as a residence by the teacher. The sole furnishings of the school were a chair, three forms and a blackboard.
In 1874 two rooms were added to the existing school to extend the teacher's residence and the school was officially renamed St Leonards School.
In 1878 three-quarters of an acre of ground was purchased.
The second school building was built in 1885. It had two rooms divided by a passageway.
By May 1901 the school roll had reached 70.
In March 1909 plans were in place to form the tennis courts and these were opened on 27 November of that year.
The King George Hall beside the school was built and opened in 1912.
The winter of 1916 saw the introduction of electric light in the schoolhouse.
The school roll continued to increase and a pre-fab building was erected west of the hall in 1949.
The pre-fab building was replaced with two classrooms, cloakrooms and offices during 1959. During this time the supper room in King George Hall was also used as a classroom.
A third classroom was added to the school in 1970, elevated above the two existing classrooms.
In 1970 the Education Board proposed to demolish the 1885 building, but was opposed by the community and ownership of this building was transferred to the School Committee.
The two rooms were used as an activity room and a library, and still have the same use today.
The 125th Jubilee celebrations were held at Labour weekend in 1993, a 140th Jubilee was held on 5 December 2008 and the 150th Jubilee was on Labour weekend in 2018.