A man who was effectively sentenced to life in prison for a robbery he committed as a teenager in Missouri has been granted parole, years after the judge who sentenced him had a change of heart.

Bobby Bostic was initially told he would not be considered for parole until he was 112 years old

The state granted parole to 42-year-old Bobby Bostic on Monday and he will be released from prison late next year, according to the American Civil Liberties Union of Missouri and the Missouri Department of Corrections.

Bostic was 16 in December 1995 when he and another teen robbed at gunpoint a group of people who were delivering Christmas presents to a needy family.

Prosecutors said Bostic fired a shot that grazed one victim, and he and the other teen then carjacked and robbed a woman before releasing her.

Then-circuit judge Evelyn Baker believed at the time it was unlikely Bostic could be rehabilitated and sentenced him to a total of 241 years in prison on 18 counts, with convictions for every count to be served one after the other, meaning he would not be eligible for parole until he was 112 years old.

She said at the time she intended for Bostic to "die in the Department of Corrections".

Bostic for a while found hope in a 2010 U.S. Supreme Court ruling that outlawed life sentences for people under 18 for non-homicide crimes. The Supreme Court, however, declined to hear his case in 2019.

But Bostic got support from any unlikely source - the judge who had sentenced him.

Baker, then retired, came to regret the sentence and in 2018 called for throwing it out, saying it was grossly unfair.

"What I learned too late is that young people's brains are not static; they are in the process of maturing," she wrote in an essay published by The Washington Post.

When the US Supreme Court denied his case, the civil liberties union worked with the Missouri Legislature to pass a law based on Bostic's case that allows teens imprisoned essentially for life for crimes other than murder to get a parole board review after 15 years.

The Missouri Department of Corrections on Tuesday confirmed Bostic is set to be released from prison on November 9, 2022.

Until then, the department will offer Bostic a variety of programs, including job readiness classes and family reunification schemes.

"We can connect him to various re-entry programs to help ensure his success in society," department spokeswoman Karen Pojmann said.