"Apparently he was coming back from Mass on Christmas morning and heading back to the barracks, their sleeping quarters, when lone mortar round came through the trailer that he was in and exploded; my understanding is that he died instantly," his brother Dr. Richard Pryor said in 2008.
Pryor was on his second tour of duty with a frontline triage unit.
Major Pryor was a surgeon at the Hospital of the University of Pennsylvania. He lived in Moorestown, Burlington County.
Pryor was married with three children.
Among the casualties of the war, Pryor, 42, dealt with were the Iraqi children.
His boss at Penn said that was one of the reasons John learned to speak Arabic.
"John learned that language so he could relate to those people and talk to them; he forced himself to do it because he didn't want a translator to be at the bedside with him when he took care of those children," Dr. William Schwab said.
Pryor joined the hospital in 1999 after graduating medical school at the State University of New York in Buffalo, Schwab said.
He described Pryor as a "star" who quickly rose through the hospital ranks to become director of its trauma program.
The reserve center is now named after the fallen citizen-soldier.