Helsingborg District Court had found the 36-year-old guilty of assault after civilian police officers filmed the wild scenes that erupted when fans of the Hammarby and Helsingborg football teams met for a prearranged battle in the town of Åstorp on October 21st 2007.
"It's quite a common phenomenon; fights like this happen several times a year," said Hans Rudolfsson, a police officer tasked with tackling fan violence.
With Hammarby fans dressed in dark colours and Helsingborg fans in light, police were able to observe as one of the Helsingborg fans fell to the ground.
Video evidence appeared to show that the Hammarby fan aimed kicks at the prone body of the Helsingborg supporter, who in line with accepted practice denied he had been the victim of assault.
"There is a sort of gentleman's code for these arranged fights and generally the rival groups try to keep things relatively clean. You're not supposed to kick somebody when they're down, for example, or throw any objects," Rudolfsson told The Local.
"But in the heat of the moment things can get out of hand, particularly if there are people involved who are drunk, on drugs, or haven't received a grounding in the culture so to speak."
The 36-year-old was initially given a suspended sentence and fined 7,500 kronor ($1,030) by the district court. But the court of appeal overturned the original ruling, arguing that it could not be proved beyond doubt that the 36-year-old's kick had connected with the body of the Helsingborg fan.
The incident took place after a large group of Hammarby fans travelling to an away match with Trelleborg disembarked from their bus to participate in an arranged fight with Helsingborg supporters on Ji-Tegatan in Åstorp.
Hans Rudolfsson said it was common for the rival factions to set up an encounter in a small town like Åstorp.
"Often the groups will arrange to meet halfway between their respective home towns, and the fights aren't always held on a matchday. It makes sense for them to meet in a small community. If the two police officers in a village turn up they're not going to be able to do much about a fight involving hundreds of people," said Rudolfsson.
The Stockholm-based officer added that police had noted a form of stratification in hooligan circles.
"There's a Sweden scene, involving groups from Stockholm, Gothenburg and Skåne, and then there's the alternative scene, which might involve, say, hockey supporters from Linköping taking on football supporters from Norrköping."
Rudolfsson said the number of people involved varied greatly.
"There can be as many as 150 from each side. But often they'll agree to have maybe ten representatives each. Perhaps it seems strange but the groups have good contact with each other, which helps with their planning."
While clubs are often powerless to take action when supporters organise fights away from a matchday arena, prosecutors have been granted the authority to issue barring orders ever since a new law came into force in 2005.
"It doesn't happen often but last year three fans from Örebro were barred from attending matches," said Rudolfsson.
A ban under the 2005 law means a nine-month prohibition from attending all first and second division games, as well as matches involving the Swedish national team, and may be extended by a year on review.