Superior Court Judge Arnold Jones ruled Thursday that 50-year-old Marvin Williams' mental status makes him ineligible for the death penalty.
Williams will spend rest of natural life behind bars for murder and then 30 years for burglary. Parole will be up to the state parole board.
"Life is precious and that has been the theme of this week," said Jones before issuing his ruling.
Earlier this week, Jones heard evidence on Williams' mental condition. He claimed that his IQ was under 70, which is considered mentally retarded.
Williams, who has scored above and below 70 on various IQ tests, argued that North Carolina law states such people cannot be executed.
Sixteen other inmates have been taken off death row. All remain in prison.
Williams is convicted of killing Theron Prince in 1989 during a robbery at a Goldsboro company where Williams worked and Price was a security guard.