Darsh Patel was part of a group of five friends from Edison who were hiking through the Apshawa Preserve, a wooded area of West Milford on Sunday, Police Chief Timothy C Storbeck said.
They ran in different directions when a black bear began to follow them.
The group noticed Patel was missing once they got to safety and immediately called police.
The West Milford Search and Rescue unit found Patel's body two hours later, Huffington Post reported.
"Evidence at the scene indicated that the victim had been attacked by a bear," Storbeck said.
A bear was found nearby and euthanised, Storbeck said.
The New Jersey State Medical Examiner, the Fish and Wildlife Division of the state Department of Environmental Protection and West Milford Police Department are investigating Patel's death.
Bears in New Jersey are most active in the fall, according to Bob Considine, a spokesman with the New Jersey Department of Environmental Protection.
"Bear sightings are not unusual by any stretch in New Jersey," Considine said.