Leighton Broughton, 25, of Osney Close in Hook Norton, has been jailed for 26 months after admitting two offences of causing grievous bodily harm without intent and one offence of assault by beating.
The sentence was imposed at Oxford Crown Court on November 6.
Both attacks took place in Banbury on separate dates.
The first incident occurred outside the Mirage nightclub on May 16.
Leon Corby was said to have made contact with Broughton on the dancefloor, after which Broughton stared at him and made him feel uncomfortable.
A confrontation followed outside the venue.
Broughton behaved aggressively towards Corby and shouted at him.
Shayde Gibbard tried to intervene but was pushed aside, constituting the assault by beating.
Broughton then struck Corby three times, causing his glasses to fall off.
Prosecutor Matt Knight said the punches had been delivered at full force.
Corby needed hospital treatment for injuries including a fractured eye socket and jaw.
Another attack took place outside Aria’s Nightclub on August 22.
Broughton and Fabio Chainho had argued in the toilets, after which Broughton waited outside for Chainho.
When Chainho walked along the street, Broughton followed him and punched him in the face, knocking him to the ground.
Chainho lost consciousness and sustained a brain bleed.
He was also required to wear a neck brace for three weeks.
The court was told that Broughton had 10 previous convictions covering 19 offences.
Gordana Austin, speaking in mitigation, said Broughton had acknowledged his responsibility and wanted to apologise to both victims.
She said his behavioural difficulties had begun at an early age, that he recognised problems with anger and acted before considering the consequences, and that his time in custody had led him to reflect on his behaviour.
Austin added that Broughton had begun addressing his substance misuse and was now drug-free, giving him greater clarity when considering his actions.
Judge Maria Lamb said Broughton had gone out in May and August, become drunk and sought an opportunity to start a fight.
She warned that someone struck in similar circumstances might not survive, noting that assaults of this kind had resulted in deaths.
The judge accepted that Broughton was remorseful but described the offences as simple thuggery arising from excessive alcohol consumption.
His total prison sentence was 26 months.