On 4 March 1914, Brother James Byrne visited the town Taiping, Perak. He suggested to the then British Resident of Perak, Sir Reginald George Watson (1913–1919), for the establishment of a Catholic boys school. His request was soon approved by the Perak State Government, and piece of land nearby the hospital was granted to him. The land was donated by the Kwa Family, one of the wealthy Chinese families of the town. The aim of the school is to provide education to boys of all religions, races and social classes, which still the main philosophy of the school. On 20 June 1914, the foundation stone was laid by the then Acting Resident of Perak, Mr Oliver Marks, and the opening ceremony was attended by prominent European families and prominent Malay rulers where most of them comprised from the State Council Members.
The school was completed on 18 January 1915, with 7 teachers, 49 students and 6 classes, housed together in the original three-storey building. The St. George's main building was designed by a colonial architect from Penang, in the mixture of Neo-Grec and Neo-Romanesque architecture, with two wings and a main porch in front (facing the Station Road). The charming building is still standing proudly today and serves as the school's front facade. The first Director of the school was Brother James Gilbert who served as the director and principal in the first year of its establishment (He later returned to served another term in 1923). The school was run by La Sallian missionaries from all around the world, however it received partial financial assistance from the State Government. After Malaya gained independence from the British Government in 1957, the school continued on as a missionary school with limited funding from the government though it was staffed with teachers from the Education Department. As from 2006, the school is funded 95% by the Ministry of Education of Malaysia.
During World War II, along with other schools in the town, St. George's was closed down. It was converted into the headquarters for the Kempetai. The rumoured brutality and torture committed by the Japanese military police during the tenure of the school is a source of ghostly legends commonly circulated by the students even till today. While the Lassalian brothers were then placed under house detention. Old boys of the school during this period time risked their lives to assist the detained missionaries. The school reopened at the end of the war along with other schools, such as SMK King Edward VII, St. John's Institution, SMK Victoria Institution and SMK St. Michael's. The school also produced significant number of prominent leaders, politicians, educationist and businessmen.