St. Mary School was the third parochial school established in the Diocese of Los Angeles. In 1907, the Sisters of the Holy Names responded to the request of Bishop Thomas Conaty, and the school was opened with grades one through eight under the administration of Sister Mary Celestin, the principal. A total enrollment of one hundred seventy-one students assembled for the solemn dedication of the school on the first Sunday of January, 1908. In September 1949, the present school property was purchased with assistance from the Cardinal McIntyre School Fund. The new school was dedicated on April 8, 1951. In 1968, the administration of the parish was assumed by the Salesian priests whose charism was focused on the education of the young with the Preventive system of St. John Bosco, their Founder. The Salesian spirit of reason, religion, and loving kindness manifested an environment of security and joy not only for the students but also for the whole school community.
In 1992, the Salesian Sisters replaced the Sisters of the Holy Names as administration of the school. Sr. Amparo Uribe, FMA assumed the role of principal, and concentrated on increasing enrollment of the school. With the help of the community, as well as the other contributors, the school began to see a significant increase in its enrollment, working and educating low income families. This challenge has been continuously met, and numerous young people continue to be educated at St. Mary. Throughout its history, St. Mary has fostered a community of faith and family spirit among its faculty, staff, students, parents and friends.
Sr. Anna Bui, FMA, was appointed as the new principal of St. Mary School in 2008. With her leadership, initiative, and dedication, the school was renovated in the summer of 2009 with the help of three generous foundations and charitable institutions: the Shea Foundation, Ahmanson Foundation and Doheny foundation. The two computer laboratories were updates with new software, computers, and equipment. The school website has been set up and the whole school has the wireless internet connection.
St. Mary School was re-dedicated on September 14, 2009 by Rev. Fr. Joseph Farias and was attended by a total of 250 people including the new superintended of Elementary Schools of the Archdiocese of Los Angeles, past principals, priests and alumni.
With the continuous improvements and changes at St. Mary school and the consistent integration of strong and solid academic education and instruction in the Catholic faith, the school strives to produce educated and devoted Catholics as well as responsible citizens who are willing and able to give service to the parish and the community.
St. Mary School is fully accredited by the Western Catholic Education Association (WCEA) and the Western Association of Schools and Colleges (WASC) and it maintains membership in the National Catholic Education Association (NCEA).