The young Regina man convicted of stabbing his former girlfriend to death with a hunting knife when he was 16 is appealing his life sentence for first-degree murder.

Skylar Prockner, now 19, got an automatic life sentence with no parole for 10 years after pleading guilty earlier this year to killing Hannah Leflar in 2015.

Prockner was sentenced as an adult after months of argument.

That lifted the publication ban on his name and gave him a life sentence.

The Crown had sought an adult sentence, while the defence had argued that the youth had no criminal record before the homicide and had mental health issues.

The court had previously heard that Prockner had trouble coping with being dumped by Leflar, and that he eventually stabbed her multiple times after hiding outside her house and waiting for the 16-year-old to walk home from school.

She was found in her Regina home by her stepfather.

At a sentencing hearing in May, the teen apologized in court saying he was unstable at the time and wants to spend the rest of his life doing good.

"I can't apologize enough for what I've done," he said at the hearing. "Everyone makes mistakes. It's what we do to right those wrongs that make us better."

Hannah was an honours student who had been named the top of her class for Grade 10 just before her death.

The sentencing hearing was told that when Leflar started dating a different boy, Prockner hatched a plan called "Project Zombify" to recruit friends to help him attack the couple with bats and knives.

The attack never took place because Leflar and that boyfriend broke up, but the youth kept tabs on her. When Prockner saw she had a new boyfriend, he stabbed her to death in her home.

A second youth, who pleaded guilty to second-degree murder, is expected to be sentenced in September.