Etuhu was caught on street cameras punching a man to the ground and then kicking him three times in an incident in Manchester a year ago.
Passing judgement today Judge David Hale said: 'You brought yourself up by your bootstraps, you and your family, having come here from Nigeria with nothing but your talent, grit and determination.
'That is a great credit to you and your family and you have blown it.'
Etuhu played 20 times in total for Cardiff, most of the appearances off the bench. The last of those the play off final defeat against Blackpool at Wembley. His elder brother Dickson plays for Fulham.