Kevin Kenny (31) died after being stabbed in the heart following a mass brawl outside popular Ruby Finnegan's pub in Ballyfermot, Dublin, in July, 2011.
Mr Kenny did not start the fight and had no involvement in organised crime.
The break-through in the investigation into his death, which was led by detectives from Ballyfermot Garda Station, happened last night when the suspect was arrested at his home.
He is due before the courts today.
The suspect was previously one of eight people arrested and questioned by detectives investigating the murder.
He is closely linked to Tallaght drug dealer Stephen O' Halloran (20) who himself was shot dead as part of a localised feud in January, 2009.
The criminal -- who is aged in his early 20s -- is also suspected of a spate of cash-in-transit robberies.
He is closely associated with a gang of young men who are linked to a spate of violent assaults, armed robberies and drug dealing.
Mr Kenny had previously cheated death in a shooting incident in 2006 when he was in a car with Mark 'Guinea Pig' Desmond.
The two men were sitting in a car at traffic lights on Old Bawn Road in Tallaght when a motorcycle pulled up alongside and the bike passenger fired from a handgun.
Although Mr Kenny required hospital treatment, he escaped more serious injury when the gun apparently jammed and the motorcycle sped away.
Mr Kenny's murder is the second terrible crime tragedy to devastate his family.
In a completely separate incident, his younger brother Martin (22) was shot dead as he lay in bed with his girlfriend in Ballyfermot in 2005.
No-one has ever been charged with the crime.
Martin Jnr, a bricklayer, was staying with his girlfriend at her home on Ballyfermot Parade on the night in 2005.
A gunman wearing a balaclava burst into the bedroom and shot him once in the neck.
Kevin and Martin, who were reportedly completely devoted to each other, have been buried side-by-side.
Kevin is survived by his father Martin, his mother, Frances, his brother, Stephen, and sisters, Samantha and Karen.