Thirty-five-year-old David Salasky was sentenced Friday in New Castle County Superior Court.
He pleaded guilty in September shortly after jury selection began in his trial for the 2011 killing of 44-year-old Joseph Szczerba.
Szczerba, an 18-year veteran of the force, was fatally stabbed while trying to arrest Salasky after a car break-in and foot pursuit. He was the first New Castle County police officer to lose his life in the line of duty since 1972.
In return for Salasky's guilty plea, prosecutors agreed to not seek the death penalty.
According to court records, Salasky has both a long criminal history and a history of mental health issues.
Defense attorneys suggested he was delusional when Szczerba was killed, and Salasky reportedly was high on chemicals known as bath salts at the time.
The Associated Press contributed to this report.