Darren McDonald, 40, travelled from Ballymena, County Antrim to support his team when he was caught on camera after the match.
He was named at the time and pictured in the media after the game that saw Hibs beat Rangers 3-2 on May 21.
At Glasgow Sheriff Court he pled guilty to running on to the pitch after the final whistle and assaulting the unknown man and kicking him on the head or body.
Sheriff Stuart Reid handed McDonald the jail time and a three and a half year football banning order.
McDonald is currently serving a sentence in Northern Ireland and the latest jail term is to start after that finishes.
Footage from the match was played to the court and newspaper reports from the time that reported the incident with McDonald were brought to the sheriff’s attention.
McDonald was seen clearly wearing a pink T-shirt and has distinctive tattoos.
The unknown Hibs fan was on pitch after the match and was on the ground, having been assaulted by someone else.
McDonald ran over to him and pulled his right leg back to kick him but slipped and fell backwards.
The court heard that the momentum meant his leg made accidental contact with the Hibs fan’s head or body.