St. Aloysius' College is situated on Mount Calvery, neighbouring St. Mary's Cathedral on one side and Sacred Heart Convent on the other. The college was established in 1895 by Jesuit fathers and was named after the Jesuit Saint, Saint Aloysius Gonzaga (born on 9 March 1568). Saint Aloysius' is regarded as the Saint of Youth by the Jesuits because of the heroic acts that he had performed when he was a young Jesuit helping Plague victims in Rome, Italy in 1587. After a few years helping plague victims, young Saint Aloysius died on 21 June 1591 at the age of 23 when he himself contracted the disease. St. Aloysius' College, Galle, is one of many schools named after Saint Aloysius, and many exist all around the world including schools in Glasgow-Scotland, Sydney-Australia, Bangalore-India, Malta, London-England etc.
Until the Sri Lankan government brought legislation for nationalisation of schools in the island (with an exception of only a few schools), St. Aloysius' College was run by Jesuit Fathers and the medium of instruction was English. The first Buddhist Principal was appointed in the year 1971 and subsequently the medium of instruction was changed to Sinhala.