Michael Briscoe is serving a life sentence for sexual assault, kidnapping and first-degree murder in the death of 13-year-old Nina Courtepatte in 2005.
A group of people lured the girl from West Edmonton Mall to the golf course, where she was raped, stabbed and beaten to death.
Briscoe was initially acquitted of the charges after testifying that he did not know of the murder plan and his only involvement was to drive the car.
The Crown won an appeal and Briscoe was convicted following a second trial in 2012.
The trial judge ruled that Briscoe did not directly commit the acts, but assisted another man, Joseph Laboucan, in the crime.
The Alberta Court of Appeal unanimously agreed in its latest decision that Briscoe has no valid grounds for appeal.
Justice Clifton O'Brien wrote that Briscoe's rights were breached when Mounties asked him to give a DNA sample without his being given the opportunity to obtain the advice of a lawyer. But the judge said that mistake wasn't "profound" and noted that officers had already pointed out Briscoe's right to speak with a lawyer, but he didn't want to.
O'Brien added that society's interest in having the case go to court weighed heavily in favour of admission of the evidence.
"Here a child was lured to an isolated place by a group of people, that included the appellant, to be sexually assaulted and murdered. Society has a substantial interest in finding and punishing those responsible," he wrote.
Along with Laboucan, three other young people were also convicted in Nina's death.
Laboucan was further found guilty of first-degree murder in the death of Ellie-May Meyer. The prostitute, who was killed two days before Courtepatte, was found in a farmer's field east of Edmonton and police connected the two killings. Briscoe was also charged in Meyer's death but acquitted.