Liam Turbett, 23, John Bennett, 37, James Nesbitt, 26, Dominic McGoldrick, 19, and Matthew Crerar, 27, were involved in the incident that descended into chaos.
Taxpayers had to stump up almost £24,000 to clean up the mess after the unofficial party in Kelvingrove Park in April 2011, which turned violent after details were circulated on Facebook.
Turbett, from Maryhill, admitted being part of a disorderly crowd, shouting, swearing and acting aggressively and escaping from lawful custody after struggling violently with police.
Bennett, from Drumchapel; Crerar, from Partick; and McGoldrick, from Darnley; pled guilty to being part of a group that struggled with police and freed Turbett from their custody.
Nesbitt, from Govanhill, admitted two charges of assault on police by throwing an item at them.
The men will all be sentenced next month at Glasgow Sheriff Court -more than two and a half years after the party in the park, thought to have involved around 6000 people.
CCTV footage of the incident, which was filmed from a police helicopter, was shown to the court.
The court heard there was no permission granted by Glasgow City Council for an event to take place.
Procurator fiscal depute Richard Hannay said: "The view the organisers took was that they had been told to have street parties and they considered it one of them. It wasn't considered to be an organised event in any sense."
It was said that around 5pm the music was switched off and the "mood changed".
The court was told the police had maintained a low presence and "turned a blind eye" to public drinking.
Footage and images were shown to the court. Turbett could be seen being held by two officers when they were surrounded by a mob - including Bennet, Crerar, and McGoldrick - who helped free him from their grasp.
The tape also showed Nesbitt picking up and launching items at police.
Turbett, a history graduate from Glasgow University, was involved in the Free Hetherington occupation in August 2011 to prevent the closure of a postgraduate club at the university. He was also a familiar face on socialist and anti-fascist demonstrations.
Bennett was sentenced to four years in 2003 for housebreaking at the High Court in Edinburgh. Defence lawyer Des Finnieston said Bennett made the "life changing decision" in 2007 to go college, then to university, and had "turned his life around in a remarkable way".