The 26-year-old, whose parents are from Macclesfield, was knocked unconscious moments after stepping in to help his partner just before Snoop Dogg was due on the main stage on Saturday night.
Off-duty paramedics who were in the audience gave the man heart-massage at the scene before stewards moved him to a 20-bed medical facility on site.
Police were called and spoke to the man when he regained consciousness.
But he deteriorated again and was rushed to North Manchester General Hospital. He has been moved to Hope Hospital where he remains in a critical condition as doctors treat a bleed to his brain.
The victim’s parents and his girlfriend are at his bedside.
Appealing for witnesses to come forward, Chief Inspector Gary Simpson said: “His family are clearly distraught. His girlfriend and parents have been with him at the hospital throughout and that’s where out thoughts are. Hopefully, he will be making a recovery but he’s still in a serious critical condition.”
Police are hunting a mixed race man who is 6ft tall and aged about 25. He is ‘muscular’ and has short curly black hair which is shaved at the sides.
Two other serious assaults also marred the event. An hour earlier, a 17-year-old boy needed 100 stitches after he was slashed across the face in an ‘unprovoked’ attack in front of the main stage.
At 7.30pm on Saturday, a knifeman slashed a 19-year-old man across the neck and arm while the victim’s 22-year-old brother had a bottle smashed over his face. Two others were also hurt as part of the same assault.
Police arrested 29 people over the weekend, the majority for drugs offences.
Defending the event, Chf Insp Simpson said: “I wouldn’t want to diminish that we’ve got a young lad lying in hospital fighting for his life. But in the grand scheme of things, 140,000 people attended Heaton Park and the overwhelming majority of that audience were good-natured, well-behaved and enjoyed themselves.
“It’s a real shame that three isolated but serious incidents in some way tarnish the event. The multi-agency plan for this operation started six months before and from a completely independent perspective I would say I have been impressed with the Parklife organisers and how seriously they take safety issues.”
