Three Holy Cross priests arrived in Santiago, Chile, on March 1, 1943, at the invitation of José María Cardinal Caro, Archbishop of Santiago, to administer Saint George's College. Fathers William Havey, Alfred Send, and Joseph Doherty believed they were going to do university work, not knowing that "college" meant a school of first through 12th graders.
St. George's was the only private school in Chile to be taken over by military government following the September 1973 coup. The Congregation returned to the school in 1986.
Originally an all-boys school, Saint George's College was made co-educational in 1973. It was initially located in the Pedro de Valdivia part of Providencia, in 1970 it was relocated to Vitacura.
Its traditional rival schools are Colegio del Verbo Divino, Colegio San Ignacio and Colegio Manquehue which were originally located near one another in the Pedro de Valdivia neighborhood of Providencia. Its traditional sister school was Colegio Santa Úrsula ("Ursulinas"), which was originally next door to St. George's in Providencia.
A group of parents and teachers, dissatisfied with the Liberation Theology measures imposed by Father Gerard Whelan during the early 1970s, broke off in 1972 and formed Colegio Tabancura, an Opus Dei-run boys' school.