The institution was founded by the Loretto Sisters (Institute of the Blessed Virgin Mary) in 1915, whose founder (Blessed Mary Ward) advocated for excellent education for young women so that they might "do great things".

In 1986 LCS opened an annex on the former site of St. Dominic Savio Catholic School on Bathurst Street to accommodate overflow from the main campus.

[2] On December 3, 1999, a fire broke out at the Brunswick building with 16 nuns escaping the blaze.

[5] Originally, the site was shared by Bishop Francis Marrocco Catholic High School, that opened in 1986.

The school's faith life also includes retreats, liturgies, charitable works and Catholic perspectives across the curriculum.