The accident happened at Route 547 and I-195 in Howell Township around 10:00 a.m.
Trooper Marc Castellano, 29, was struck while assisting with a search of a wooded area for two occupants of an abandoned vehicle. They were wanted for a violent crime.
Castellano suffered multiple injuries. He was taken to Jersey Shore Medical Center in Neptune New Jersey, where he later died.
Roads in the area were closed while police investigated this accident.
The abandoned vehicle was found on Interstate 195 westbound on the ramp at exit 31 in Howell Township.
The abandoned auto's driver, 30-year-old Diana Hoffman of Blackwood, was later found hiding nearby in the woods and was taken into custody.
Hoffman told authorities that a man was riding with her, and dozens of troopers, local police and other law enforcement personnel spent hours looking for him.
Investigators were "questioning the validity" of Hoffman's claims, and charges against her were pending.
Hoffman's auto was not the vehicle that hit Castellano, a married father of two young children who had been a trooper for five years and was a member of the Troop "C" Tactical Patrol Unit.
Trooper Castellano was a five year New Jersey State Police veteran, graduating as a member of the 136th New Jersey State Police Academy Training Class in September of 2004.
"The loss of Trooper Castellano is a difficult blow to absorb," said State Police Superintendent Colonel Rick Fuentes. "The New Jersey State Police prides itself on being a family and the loss of our brother will be felt throughout the entire Division of State Police."
Four law enforcement officials were taken to a local hospital for treatment related to heat exhaustion during the day, but no other health-related problems were reported.
Gov. Chris Christie had gone to the hospital earlier in the day to visit with Castellano's family, as did Fuentes. And during a media availability in Mahwah, the governor had urged people to pray for Castellano and his family.
Fuentes said Castellano was "the embodiment of the finest ideals" of the state police force.