He defeated American wrestler J'den Cox 2-0 in the final match of the 92kg.
Ghasempour was put on the shot clock in the first period and responded by scoring a takedown, the only point of the match. There was no scoring in the second period.
It was Iran’s first gold medal in the competition underway in Belgrade, Serbia.
Earlier on Saturday, Younes Emami of Iran also claimed a bronze medal in competitions.
Emami defeated Azerbaijan’s Turan Bayramov 8-4 in the men's freestyle 74kg. Gold medal went to American wrestler Kyle Dake who defeated Tajmuraz Salkazanov from Slovakia 3-1 in the final.
Mohammad Nokhodi in 79kg and Hassan Yazdani in 86kg had previously won two silver medals in the competition.
ZZ/TT