Paul Boss, aged 49, of Calthorpe Street, Banbury was sentenced at Oxford Crown Court to six years and 10 months’ imprisonment.
He pleaded guilty to one count of wounding with intent to cause grievous bodily harm and one count of assault by beating.
One count of racially aggravated common assault was ordered to lie on file.
On 30 August 2020, Boss assaulted two men in the Three Pigeons Public House on Southam Road, Banbury. He threw a pint glass at a member of staff, narrowly missing his head. When a customer tried to stop Boss, he assaulted him and bit off part of his ear.
The victim, a man in his thirties, sustained irreversible damage to his ear, which now requires plastic surgery.
Boss was arrested the same day and charged on 31 August.
Investigating officer, Detective Constable Gareth Steward, based at Banbury police station said: “This was a horrific attack on an innocent member of the public and the landlord of the pub.
“Boss set out to cause serious harm to someone that day for reasons that are only known to him.
“I hope this sentence provides some comfort to the victim who now has to carry the physical and mental scars of this assault with him.”