Graspop was not originally a heavy metal festival; rather, it was conceived as a local family rock festival, first organised in 1986. In 1995, the headliners were Joe Cocker and Simple Minds. However, due to the public being oversaturated with family festivals, the number of visitors had dropped to an all-time low.

Founder Peter Van Geel realised that mainstream rock music held insufficient appeal to festival visitors. Reflecting on the most memorable acts of the preceding years (Motörhead, Ramones, Paradise Lost, and so forth) and on his own musical preferences, he decided in favour of a drastic reorientation.

Despite the small size of the festival grounds (upholding a perimeter of only ~4 km) the festival draws a large number of spectators from around Europe, with a total of 220,000 visitors in 2022, up from 200,000 visitors over the course of the 2019.