In 1952, the schools in Downers Grove were overcrowded because of the number of babies born after WWII. The overcrowding was such a problem that some students attended school at the Methodist Church and first graders only went for half days. Finally, Downers Grove decided to open more schools. One of them was Hillcrest School.

Hillcrest School opened Monday, February 18, 1952, and was named after the street that runs perpendicular to the school. At that time, Hillcrest was considered to be in southwest Downers Grove. There were fewer homes and the area was considered rural. To the south and west, farmers tended small farms that grew crops like corn, beans, and wheat. They raised livestock such as cows, horses, pigs, geese, and chickens. One lady even had beehives and collected honey. Students at Hillcrest had to watch out for hungry, angry bees.

In 1952, a reporter described the school as a "low, one-story brick structure with wide expanses of glass." Little did they know how it would change! The first addition in 1957 was the middle wing that now holds the third, sixth, and most of the fifth graders. The stage and gym also were added at that time. In 1962, a second addition was built and the final wing was added. This extension is where the current kindergarten through second grades are located. The final addition, constructed in 1993, added two new classrooms across from the gym, the Learning Resource Center, the computer lab, the offices, and a foyer area. The area that is now the activity room was remodeled so the music and art programs could be taught in that space.