Liljeström, who runs the Christian website Bibeltemplet, was previously sentenced to one month in prison by the Court of Appeal for allowing the publication of hateful comments about homosexuality.
He was originally sentenced to two months in jail for incitement to hatred by Stenungsund District Court.
A relieved Liljeström, 50, was notified of Wednesday's Supreme Court's decision by news agency TT.
"Has the verdict arrived? A not guilty verdict? That's very good to hear. I actually had a feeling that it would turn out like this. I did what Christians do and asked God. I then got a feeling that it was going to work out well," he said.
The court ruled that Liljeström may not have been fully aware that the comments posted by visitors to the website constituted incitement to hatred. He told the court that he had thought long and hard about removing the offending posts before eventually allowing them to remain on the site where they could serve to generate further discussion, Dagens Nyheter reports.
One of the more extreme comments posted by a visitor to a discussion forum thread entitled 'Sodomy' asserted that "men who cannot summon up the energy to abstain from intercourse with other men should be sentenced to death and hanged from posts in the town square." Although he did not remove it, Leifström did in fact criticize this statement and several others on the site's discussion forum.
The Supreme Court ruling was not unanimous, with two judges calling for a conviction. The judges, Per Virdesten and Ella Nyström, argued that "the statements [posted to the website] went far beyond the bounds of reasoned debate and can be considered deeply insulting to homosexuals as a group".