Police say 58-year-old Trooper Donald C. Brackett was found unresponsive outside of his patrol vehicle suffering from an apparent medical episode.
Trooper Brackett was rushed to Jefferson Torresdale Hospital but could not be saved.
"All personnel of the Pennsylvania State Police are deeply affected by this loss," said Lieutenant Colonel Evanchick. "Our thoughts are with Trooper Brackett's family and friends as they mourn his sudden passing."
Trooper Brackett enlisted in the Pennsylvania State Police in October 2001. He was assigned to the Patrol Section of Troop T, King of Prussia at the time of his death.
Trooper Brackett was also a veteran of the United States Marine Corps.
Pennsylvania Governor Tom Wolf has ordered the commonwealth flags to fly at half-staff in honor of Brackett. The flags are ordered to be lowered until sunset on Wednesday.