Truro House premises were first used as a barracks for soldiers in the First World War. In 1914 the nuns owned the buildings, using it as a hostel. What is currently used as the school library was originally the kitchen of the home, belonging to the Gowie family.  It was used as a dispensary by the nuns during the war. They gave medicines to all soldiers, regardless of their race or country of origin.

 In 1928 additions were made to this complex, and it was then used as a hostel for Training College ladies up to 1947. The school acquired the old Graeme College Hostel building, on Donkin Street, when Graeme College was relocated across town in 1975. The old coal shed for the Graeme College hostel together with the toilet block, have, in 2010, been renovated into a two bed-roomed cottage for rentals.  Both these buildings are fully used at Festivals for Art Exhibitions.

In 1948, the school was named after the Acting Administrator of the Eastern Cape, Mr Johan Carinus, who saw the need to revitalize Education in the Province.  The first Principal of the school was Sister Lilian Francis, followed by Mrs Molly Brown and Mr Jack Meyer, subsequently an inspector of Education. It was in his tenure that the school became Government owned.  Mr Louw Erasmus was subsequently principal for 25 years. Mr Tony Swift then took over and remained for 20 years, until 2006.  Mrs Ginny Reed took over from Tony Swift in 2007 and retired at the end of 2013. Michele Kloppers has been in the position since 2014.

Carinus campus