William Greig, 35, attacked Darren Ellison outside Chalky’s Bar on Picardy Place after a drinking session following an 11-hour shift.
In the assault – dubbed “barbaric” by a sheriff – Mr Ellison was headbutted and fell to the ground before being kicked and punched several times.
Greig, known to his friends as Billy, also bit Mr Ellison on the nose and seized him by the head during the attack in the early hours of August 22.
Sheriff Thomas Welsh branded the case “astonishing”, and said: “It was barbaric, literally barbaric, to bite somebody’s nose like that.” Edinburgh Sheriff Court heard that Mr Ellison had been living with Greig, and the pair had known each other for a decade.
Greig’s defence agent Angus McLennan said his client, who had recently separated from his wife, had very limited memory of the incident but took full responsibility for his actions.
He said: “He was extremely emotional about the separation.
“He felt a great deal of shame that he was the first person in his family to be going through a divorce.
“The events are clouded by drink – there’s no excuse.
“It’s his belief that there was some sort of comment made by Mr Ellison regarding his separation.”
Mr Ellison was taken to hospital after the incident but later discharged himself and did not require any treatment.
The court heard how Mr Ellison suffered “no lasting damage” from the attack, which happened at around 2.25am.
Sheriff Welsh was told that Greig’s employer had been “entirely supportive” and even loaned the chef money to pay his legal fees.
Greig, of Muirhouse Place West, has not seen or spoken to Mr Ellison – who no longer works at the restaurant – since the assault, but wanted to apologise to him directly.
The defence lawyer insisted the attack had been an “isolated incident” and stressed that Greig had also pledged to curb his drinking habits.
He added: “He is by no means an alcoholic but he recognises that alcohol was a significant trigger to how he behaved.”
Sheriff Welsh told Greig he had considered handing down a prison sentence due to the “savage nature of the attack”.
He said: “You should be thoroughly ashamed of yourself. It was disgraceful conduct. There is absolutely no mitigation for behaviour like this in a public place in attacking your colleague in the way that you did.
“It’s the kind of conduct that results in the same ferocity of punishment as you injected into the act.”
But the sheriff was persuaded not to send Greig to prison because he was a first offender.
Instead, Greig will have to carry out 200 hours of unpaid work and pay Mr Ellison £300 in compensation.
Sheriff Welsh added: “I warn you that if you end up back in front of me for breaching the order or not paying the sum, I can sentence you to 12 months in prison. That is what some sheriffs would have done.”