The 14-year veteran police officer had a heart attack and collapsed, Spiroff said.
Two UMBC students found the 43-year-old and one called 911 while the other performed CPR, Spiroff said.
Senior Antigone Cox, 22, said she was walking to her car about to run some errands when she saw a man jogging but paid little attention because people often run around UMBC's Hilltop Circle loop.
After the environmental science and biology major made a U-turn, she saw the jogger collapse. She immediately pulled over, called 911 and approached the man, she said.
Shortly after Cox got to the man, Chris Tingley, a 20-year-old junior studying emergency health services at the university, arrived.
Tingley was driving to the grocery store when he saw a man on the ground between Poplar and Center roads on UMBC's loop, he said.
"I was hoping it wasn't what I thought it was, but it was," said Tingley, who has worked as a volunteer EMT at Howard County Station 2 for two years.
Tingley said Miller, a married father of one, had a bloodied face and was told Miller had fallen to his knees before hitting his head on the ground.
As Cox stayed on the line with the dispatcher, Tingley rolled Miller over and checked his pulse just as a Baltimore County police officer arrived, he said.
When he determined that Miller, an Air Force veteran, did not have a pulse, Tingley said he began CPR.
He estimated it was five minutes before paramedics arrived. The responders used a defibrillator at the scene then took Miller to St. Agnes Hospital.
Cox said she hung up with the dispatcher after the police officer arrived, then made more calls.
"I called my friends to spread the word to pray for him," Cox said.
Tingley and Cox, who did not know each other before the incident, visited Miller three days after the accident and Miller stood up and shook their hands.
Spiroff called Miller's recovery "remarkable" and said he was "fully cognizant" when he saw him on Friday.
"The danger zone was, they were worried about brain activity," Spiroff said. "He was out with the heart attack for a while before he got attention."
Lt. Nancy Stork said Miller had remained in the hospital's coronary care unit until the day of his release.This story has been updated.