To carry out the mission of St. John Baptist de La Salle for the poor and the working class, St. Joseph School - La Salle started with the establishment of Immaculate Conception Free School in 1954 by the De La Salle Brothers and the Young Ladies' Association of Charity (YLAC), to serve the educational needs of the children of sugar plantation farmers in Barrio Obrero, Bacolod City.

The St. Joseph's High School was established in 1960 to provide secondary education to the first 45 graduates of the Immaculate Conception Free School who were charged minimum fees. Eventually, they took in pupils from Barrio Obrero Elementary School. The De La Salle Brothers established an adult night high school in 1966. Inflation and sudden fluctuations in sugar prices in the latter part of the 60's brought about the decrease of financial support from benefactors who helped run the Immaculate Conception Free School, which was later closed in 1971.

Through the years, the institution has found enough support to sustain development and remain as a resource to Barangay Villamonte, which now has a population of 34,000. As it celebrates its 50th anniversary, SJS-LS hopes to continue serving the children of poor families in Negros, in the Founder's name.