The Florida Board of Executive Clemency voted unanimously to pardon Morrison, who was still appealing the verdict when he died suddenly in Paris in 1971.
Morrison's widow, Patricia Kennealy Morrison, had opposed the pardon on the grounds that Morrison never exposed himself to the crowd as prosecutors alleged.
'Since the original charges and trial were a publicity stunt to begin with, it doesn't surprise me in the slightest that the pardon should follow in those footsteps,' she told CNN. Her husband 'did nothing to be pardoned for' and his record should have been expunged, Patricia Morrison said.
'Despite the fact that there were 10,000 people in the hall that night, funny thing, no one has a picture of the actual exposure of the Lizard King's lizard,' said Morrison, using a popular nickname for the notorious rocker.
The pardon was championed by outgoing Florida Governor Charlie Crist who said the conviction should have been dismissed after Morrison's death 'so that he was again presumed innocent.'
'A pardon corrects the fact that Mr Morrison is now unable to take advantage of the presumption of innocence that is the cornerstone of the American criminal justice system,' Crist said in a statement after the vote.