Marshall was indicted earlier in the day on the charges, and then he pleaded guilty, authorities said.
Judge Michael Hall sentenced Marshall to two consecutive life-without-parole sentences and 33 and half more years for other felony charges.
A victims’ advocate, Skye McKenna, said the family was happy with the judges’ decision.
McKenna said, “We feel Gary has mercy for life in prison with no parole. We believe he has no conscious.”
Marshall was living with his parents, David and Susie Marshall, in their Union home when he killed his parents.
Marshall appeared in court, but did not say anything. His attorneys told the judge that their client was remorseful for what happened.
“We have no doubt he will do it again to get what he wants if ever released from prison. Gary, the sorrow you caused will always be with us,” Skye said.
David Marshall was 65 and Susie Marshall was 61. They were found inside their Greencliff Drive home. Officers were called there to check on the welfare of the couple who had not been heard from for days.
He was finally arrested at a Shelby County motel a week later with his parent’s blood still on his clothing.
Officers said Gary Marshall was stealing his parent’s credit cards and prescription drugs and pawning his dad’s guns for cash.
The death penalty specification was optional for this case, but court officials said that was not the family’s wish. Also, as part of the plea deal, Gary Marshall is unable to file any appeals.