Karl Loche carried out the attack in the car park of the hotel in Featherstone where he had been staying while he took part in an electricians’ course.
Leeds Crown Court heard the victim was also training to be an electrician and the attack happened during a celebration to mark the end of the course.
Michael Smith, prosecuting, said the incident took place in the early hours of November 2, 2017.
The victim and another man had been out for a meal and returned to the hotel to continue drinking.
Mr Smith said Loche and the victim “clashed” during the evening. Loche swore at the victim and accused him stealing his car keys.
The defendant carried out the attack when the victim went to confront him outside. A witnessed filmed the attack on his phone. Loche was carrying a torch in one hand as he threw three punches which made contact with the victim’s head.
The footage showed the victim fall forward onto the floor. Loche walked away as the victim lay unconscious.
He suffered fractures to his face, nasal bone and eye socket.
Loche, 27, of Mansel Street, Grimsby, pleaded guilty causing grievous bodily harm.
The court heard Loche has previous convictions for drink-related violence.
Shila Whitehead, mitigating, said Loche pleaded guilty at the first opportunity and had been out of trouble in the 15 months since the offence.
Judge Tom Bayliss, QC, said: “Your reaction was to walk away. You didn’t even call an ambulance. You left him unconscious on the floor.”