Founded in 1818, it is the oldest secondary educational institution in the United States west of the Mississippi River, and one of the largest private high schools in Missouri.

Classes were held in a one-story house owned by Madame Alvarez on the northwest corner of Third and Market Street.

[4][5] The high school integrated when it enrolled John Carter, a sophomore transfer from Saint Thomas Academy in St. Paul, Minnesota, in 1946, one year before Cardinal Joseph Ritter issued a pastoral letter desegregating all Catholic schools in the St. Louis Archdiocese.

In each year from 2013 to 2016, SLUH was named among the top-scoring organizations in the mid-size employer category of the St. Louis Post-Dispatch's survey of Top Workplaces.

[14] In 2010, 23 students from SLUH were named National Merit Scholarship Program Semifinalists, more than any other school in Missouri.

[22] In 1999, educational exchange programs for the study of Russian language and culture were established with schools in St.

[23][24] In keeping with its strong Jesuit Catholic heritage, courses in Latin and Greek are offered, as are the popular choices of French, Spanish, Arabic, and Chinese.

This was highlighted by the construction of the Robertson Library and the development of property fronting Oakland Avenue, including the football stadium and upper parking lot.

Development continued in the 1990s with the inauguration of the performing arts wing highlighted by a 610-seat theater, named after longtime drama teacher Joseph Schulte in the 2000s.

The Jesuits also moved out of the Backer Memorial building around this time and into nearby houses the school purchased: the "J-wing" then became home to the theology department, several classrooms, and the administrative offices.

In the late 1990s, a large capital campaign to fund growth and expansion projects began under Fr.

[34] The physical improvements began in 2004 when the football stadium was given artificial turf[35] and a new entry boulevard to the west of the campus was constructed jointly with the adjacent St. Louis Science Center, along with a new shared parking facility.

SLUH was the top-scoring high school in the Missouri chapter of Math League for five years running.

In addition, they field teams in multiple other sports such as racquetball, target shooting, inline hockey, rugby union, and ultimate frisbee.