James N Burmeister, 21, was convicted of two counts of first-degree murder and conspiracy in the shootings of Jackie Burden and Michael James on 7 December 1995. The murder convictions mean he could face the death penalty.
Burmeister showed no emotion as the verdict was read, but his mother, Kathy, sobbed in the row of seats behind him.
Outside the Cumberland County courthouse, Mary Lou Burden, Jackie Burden's mother, raised her arms in victory and said she hoped her daughter's killer would get the death penalty.
"I'm so happy ... I can't talk, I'm so happy," she said.
The Cumberland County Superior Court jurors took more than 10 hours over three days to reach their verdicts.
Jurors looked at autopsy photos and reports and examined testimony by a state witness, former soldier Randy Meadows, who said that he had driven the car to the murder scene.