Mark Lavelle (32) originally from Bollingbrook, Swinford in Co Mayo but with an address at Basin Street, Dublin 8, pleaded guilty to assaulting causing harm to the Dublin and Na Fianna footballer in the early hours of September 20, 2014 at Dorset Street Upper in Dublin 7.
Mr Cooper received nine stab wounds to his forehead, eyelid and neck area. He spent one night in hospital.
He had no recollection of the assault and gardaí were called to the scene after a passing taxi driver noticed the footballer stumbling along Dorset Street with his back covered in blood.
Officers later followed a trail of blood from where they met Mr Cooper to a nearby chipper and secured CCTV footage from the restaurant. Lavelle was later nominated as a suspect by four gardaí after viewing stills.
Lavelle was in detention at the time being questioned about an unrelated crime when he asked gardaí; “How was the Dublin footballer? Who was stabbed? Was it Jonny Cooper? Was it a random attack or did they know he played for Dublin?”
Garda Leslie O'Rourke told John Fitzgerald BL, prosecuting that during Lavelle's questioning in the station for the other incident, a blood stained jacket and knife were taken from him. These were later analysed and Mr Cooper's blood was found both on the knife and the cuff of the sleeve of the jacket.
Lavelle was arrested from Cloverhill Prison on September 29, 2014 and charged with the assault.
A brief victim impact report before the court stated that Mr Cooper was out of work for two weeks and although he has facial scars it his understanding that they will fade in time.
He said he was constantly looking over his shoulder in the aftermath of the attack and was apprehensive going to work. His family were also concerned for him.
Lavelle's 62 previous convictions include assaults, criminal damage, possession of knives, possession of drugs, burglary, robbery, violent behaviour in a garda station, trespass, public order and altering a prescription.