Kaj Linna was sentenced to life in prison in 2004, accused of brutally murdering someone during a robbery in the remote village of Kalamark.
In December, he was granted a new trial at the Appeals Court after journalistic investigations by Swedish Television and Dagens Nyheter, among others, found flaws in the original police investigation.
He was released by Sweden's Supreme Court on Tuesday on the final day of the nine-day retrial.
"After the court had held a private discussion, it was decided that the prison sentence with which he had previously been convicted could not be enforced until further notice," the court wrote in a press statement.
"That means that the sentenced man should immediately be set free while waiting for the judgement of the Supreme Court."
"I was standing up there in the windows looking down on you all," Kaj Linna told Swedish Television when he was released. "I'm going to try and get myself a ticket out of here."
"It feels extraordinary," added Carita Postma Kaukosalo, his sister.
Linna's lawyers petitioned for a new trial three times before the Supreme Court granted his wish in December last year.
There was no technical evidence in the case, which is based chiefly on a witness who said that Linna told him about plans to rob the two brothers in their home.
The witness also said that a few days before the murder, he had travelled to Kalamark with Linna in an attempt to convince him that it was not worth robbing the brothers.
In their petition for a fresh trial, Linna's lawyer presented a long, newly recorded film from the star witness, aimed at showing that he gave incorrect information, and that he has changed his story on several crucial points.
Ahead of his new day in court, Kaj Linna, now in his 50's, told Swedish Radio's local channel in Norrbotten that he was expecting that the trial would lead to his release, after 13 years in prison.
"I am counting on being released. But I can't be 100 per cent sure, because I have understood that when it comes to courts it is all a bit of a lottery," he said.