Michael Daniels was sentenced in Bamberg on Monday after pleading guilty to murder and two counts of attempted murder.
Authorities say Daniels went into an Olar convenience store Nov. 1 and killed Alicia Dyches and wounded another employee and a customer.
Authorities say Dyches' father said Daniels harassed his daughter in the weeks before the killing. Daniels screamed profanities at Dyches' sister during a Nov. 3 hearing, moments before a judge denied him bond.
Days after his arrest, authorities put Daniels under observation after he slashed his throat with a broken light bulb.