[7] In October 1946, the school's cafeteria was largely destroyed by a fire that was blamed on a recently installed Coca-Cola vending machine.

In late 1967, the school board proposed a redistricting move that would send all Warrenville students to the newer Wheaton North building.

[9] In January 1968, the board approved bussing underclass students in Warrenville to Wheaton North, and allowing upperclassmen the choice of either school.

[10] The current building that houses Wheaton Warrenville South was opened in 1973, and operated as Wheaton-Warrenville High School from 1973 to 1983.

[7] By 1982, it was clear that the high school population in the district was shrinking, and there would be a need to close either the older, tradition rich Wheaton Central, or the newer, but smaller Wheaton-Warrenville.

[13] When the request for the mass transfer was not granted by the board, a group of Warrenville parents began threatening to secede from the district.

[14] In January 1983, the parent group presented a petition signed by over 75% of the registered voters of Warrenville to approve detaching from the district.

[17] The issue finally came to an end when the DuPage Valley Regional Board of School Trustees voted 5–2 to reject the secession bid.

[23][24] The building comprises five major pods: Grange, completed in 2005, and Tradition, Scholarship, Commitment, and Integrity, which are taken from the school seal.

In 2002, The Tradition and Commitment pods, primarily housing the English and Science departments, respectively, underwent significant renovations with reconstruction of all second floor classrooms.

Wheaton Warrenville South installed solar panels on the roof of the school as an alternative energy source as part of a 2004 partnership with British Petroleum.

The second phase began in spring 2005 and was completed by May 2006 and consisted primarily of renovations to the athletics wing and the construction of the field house.

[32] Wheaton Warrenville South is also a member of the Illinois High School Association (IHSA), which oversees most sports and competitive activities in the state.

The school sponsors interscholastic athletic teams for young men and women in: basketball, cross country, golf, gymnastics, lacrosse, soccer, swimming & diving, tennis, track & field, and volleyball.

The following competitive activities have finished in the top four of their respective IHSA sponsored state championship tournament or meet:[34]