Liam Thornton grabbed his victim at the Dejavu nightclub in Blyth, Northumberland, last August and "clamped on" to his ear.
Newcastle Crown Court heard the bite tore off an outer portion of the ear and some of the cartilage.
The victim had reconstructive surgery but the ear has been left permanently changed.
Thornton, who is in a relationship with his victim's ex, admitted wounding with intent.
Judge Penny Moreland jailed the 24-year-old, of Bowes Court, Blyth, for 27 months.
The judge told him: "You grabbed him and bit his ear.
"You boasted later you had chewed his ear off and left him scarred for life."
Judge Moreland said the boasts, which were in messages Thornton had sent after the attack, appeared to show he was "pleased about what you had done and proud of it".
The court heard Thornton has never been in trouble before, has good employment, a stable relationship and health problems.
Richard Bloomfield, defending, handed in references on Thornton's behalf, which he said "speak well of him".