Army Captain Bradley Grimm, who is based at Al-Asad airbase in Iraq's Anbar province, had "helped develop a system to speed the flow of intelligence from here on the ground to various national capitals," Baghdad-based spokesman Colonel Steve Warren said.
Grimm gleaned "actionable intelligence" from "captured documents" belonging
to foreign fighters with ties to Denmark, Warren said.
"Brad's work likely saved the lives of Danish citizens," Warren said, without providing additional details of the plot itself.
For his work, Denmark awarded Grimm the Danish Defense Medal for Special Meritorious Effort.
The intelligence-sharing system he helped develop contributed to the arrest of a suspect in the school plot and the confiscation of some homemade explosives.
Denmark is an active member of the approximately 65-nation coalition conducting operations against Isis fighters in Iraq and Syria.
Danish lawmakers on Tuesday approved a plan to commit several F-16 warplanes, a transport aircraft and 400 military personnel to expand the country's fight.