Harrell, 41, also has been charged with bringing controlled substances into jail.
The musician allegedly was speeding Friday night when his car hit a pickup truck, sending it down an embankment and killing the driver, Paul Howard Shoulders, who was not wearing a seat-belt and was ejected from the vehicle.
Police told CNN the musician showed signs of impairment at the time of the incident and admitted he drank hard cider and took Lortab and Xanax before getting behind the wheel.
After he was arrested, police allegedly found a plastic bag concealed in Harrell's sock, which contained eight Xanax pills, 24 oxycodone pills and four oxymorphone pills.
He remained in jail Monday morning in lieu of $100,000 bond, CNN said.