A jury found Tavaria Brunson, 18, guilty Wednesday of murder, attempted murder, armed robbery, burglary and possession of weapon during commission of crime.
The judge sentenced him to life in prison plus 80 years.
Last April, Brunson shot and killed Chris Deaver, 33, at his job at Rick's Pawn Shop on West Lucas Street in Florence.
Florence police say Brunson walked into the pawn shop and opened fire. They say he shot Deaver at point blank range.
Brunson shot Deaver's co-worker, Donna Robinson, in the eye.
Deaver was a well-loved musician in Florence. His fellow musicians have held a number of benefits since the killing to benefit Deaver's five-year-old daughter.