Jurors in Dauphin County deliberated for about three hours before convicting 19-year-old Kermit Pittman on Friday of first- and second-degree murder and robbery.
Prosecutors said security camera footage and fingerprint and DNA evidence linked Pittman to the January 2011 murder of 47-year-old Florentino Dejesus-Lopez.
The video showed a masked man entering the Steelton store and immediately opening fire with a rifle. Dejesus-Lopez was shot five times.
Defense attorneys Jessica Bush and Gregory Mills argued that the evidence wasn't conclusive and police had the wrong man.
Judge Andrew Dowling told the victim's daughter that he hoped the sentence would comfort relatives but added "It's difficult to imagine any comfort in this matter."