Aroostook County Superior Court Judge Harold Stewart ordered Marcus Asante, 23, of Massachusetts to be taken to the state's maximum security prison.
In November last year, a jury found Asante guilty of murder in connection with October 2016 robbery and murder of 31-year-old Douglas Morin of Oakfield.
Three others were also charged with murder in connection with Morin's death.
They have all entered guilty pleas.
Two of them have been sentenced to jail time, while the third is waiting to find out how long he'll spend in prison.