Johnson is a convicted felon and wasn't allowed to carry a gun when Grove pulled him over, suspecting him of deer poaching.
He shot at Grove 15 times before killing him.
When Johnson took the stand today, he apologized to the victim's family and said he was sorry for the pain he's caused them and that there's nothing he can do to bring Grove back.
The jury convicted him of first-degree murder and on Thursday night sentenced him to death.
The victim, David Grove, grew up in Waynesboro. He graduated from Grace Academy and attended the Penn State Mont Alto campus.