Barton Left 16-Year Old With Broken Teeth!
Judge Henry Globe described the player as "aggressive and disgraceful".
Newcastle are currently considering the implications of Barton's sentence, which also included four months concurrently imposed for affray and £2,500 compensation order to his 16-year-old victim.
Barton, cousin Nadine Wilson, 27, and brother Andrew Barton, 20, were captured on CCTV in a number of violent incidents in Liverpool city centre on December 27 last year.
It took place as Barton was on bail for another alleged assault.
At around 5am the player, who had consumed 10 pints of lager and five bottles of lager, went into a McDonald's restaurant with his brother and Wilson.
The court heard Wilson became involved in a confrontation with a group of youths and the row continued outside the restaurant, with Barton caught on CCTV knocking an unidentified man to the ground.
He then straddled the man, and punched him four or five times as Wilson threw food at the victim before Barton punched him up to 15 times more.
Minutes later, the player attacked 16-year-old Jordan Spencer, punching him in the mistaken belief the youth had slapped Wilson. The punch broke a number of Mr Spencer's teeth.
Ian Harris, prosecuting, described the incident as "violent and cowardly".
Their half-brother Michael is serving life for the racist murder of Anthony Walker in Huyton, Merseyside in 2005.
Peter Kay, of the Sporting Chance clinic in Hampshire which has been supporting Barton since January, said the player had an alcohol problem.
Judge Globe told Barton: "Without doubt, the most serious of the three offenders is you.
"You acted in an extremely violent and aggressive manner.
"You have a high profile as a footballer and you know that draws attention to you. Yet you drank to excess and behaved in an aggressive, disgraceful manner."