Buchanan housed his fledgling school in two identical specifically designed buildings, one on East Suffolk Road in Newington, the other on Egypt Terrace (now part of Cluny Drive) in Morningside.

Prior to the school's opening on 1 October 1890, Buchanan had placed daily adverts in The Scotsman'; giving out handbills to local businesses and creating a prospectus for parents.

[1] His wife, Annie Custance Buchanan (née Carr) was appointed as Principal and, despite having a young family to look after, threw herself into the role.

There was a considerable amount of damage and girls had to be taught temporarily at the Livingstone Halls on Clerk Street (now a video rental shop).

In 1929, she sold the Newington school to Miss Matthew, who decided to keep the name St. Margaret's (a decision that much pleased Mrs Buchanan).

[1] Prior to buying the school and taking on the role as Principal, Miss Matthew was already established at St. Margaret's, being a Housemistress and a teacher of Latin.

In 1960, Miss Matthew decided to transfer the school from private ownership to a Company Limited by Guarantee, to be administered by a Board of Governors.

The building of Matthew House was completed in 1972, and extensive refurbishment work was carried out on the Pavilion and the science laboratories.

In 1965 the school celebrated its 75th anniversary, and to commemorate this the daughters of Mr and Mrs Buchanan donated a plaque.

In 1967 a Clothing Exchange which enabled the purchase of second-hand uniform was established, and continued until the closure of the school.