Khadr spent a decade at Guantanamo, the U.S. naval base in Cuba. In September 2012, he was transferred to Canada to serve the remainder of his sentence. He was first incarcerated largely in isolation at the maximum security Millhaven Institution in eastern Ontario before moving to Edmonton in May.
Edney had argued that an eight-year sentence for the murder and four other crimes only made sense as a youth sentence.
But the federal government argued that Khadr was given eight years as a youth for murder and the sentences on the four remaining offences were to be served concurrently as an adult.
Rooke agreed that Khadr was sentenced as a youth on the murder charge and as an adult on the four other charges. The issue then became where best to serve the sentence.
"Mr. Khadr obviously cannot be in an adult provincial facility for adults and a penitentiary at the same time," Rooke wrote.
"Therefore, the question is where is the offender sentenced to youth and adult sentences to serve that sentence?"
Given that part of Khadr's sentence is being served as an adult, Rooke found that his placement in a penitentiary is lawful.
Edney said his client plans to appeal.
"We say that Omar Khadr's eight-year sentence could only have been a youth sentence had those offences been committed in Canada. This judge disagrees. And so we will take that argument to the Court of Appeal and let the Court of Appeal make that determination on whether he is right or whether we are right," said Edney.
The federal government welcomed the ruling.
"Omar Ahmed Khadr pleaded guilty to heinous crimes, including the murder of American Army medic Sgt. Christopher Speer," Jean-Christophe de Le Rue, a spokesman for the minister of public safety, said. "The government of Canada will continue to vigorously defend against any attempt to lessen his punishment for these crimes."
The federal government has insisted that Khadr is a dangerous terrorist who deserves to be treated as such.
Khadr was eligible for full parole in July, but hasn't applied. Edney said that because Khadr has been so isolated, he hasn't been eligible for prison programs that could help with his parole application.