Connor Smith, 19, "turned" on work colleague Anil Jnagal during a night out on Birmingham's Broad Street, the city's crown court heard.
He was drunk and had cannabis before attacking Mr Jnagal, who had been trying to calm him down.
Smith admitted wounding and his barrister said he was remorseful but added "nothing is going to bring the complainant's ear back".
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Prosecutor Tariq Shakoor said Smith, of Summerlee Road, worked with Mr Jnagal, 25, at a branch of Harvester in Birmingham's Star City leisure complex.
He told the court the victim remembered Smith "turning on him" and the pair fell to the floor, where the defendant bit his ear.
The court heard reconstructive surgery was unlikely due to the nature of the injury.
Jonathan Barker, defending, said Smith was in an emotional state at the time of the attack due to the recent death of his aunt.
Sentencing, Judge Richard Bond, said: "All the victim did was to try and stop you being aggressive towards others.
"It ended up with you quite deliberately using your teeth as a weapon and you bit off a really large chunk. About half of his ear has completely disappeared.
"This is not something that happens in a millisecond - to bite through somebody's ear takes real determination and a real effort."
A man who bit off half his friend's ear has been jailed for two years.