Brett Edwards had chased his "petrified" victim over the Jubilee Way dual carriageway to a car park near the Central Methodist Church.
The court heard the man jumped over a 20 to 25ft high wall in an attempt to escape Edwards and suffered a broken leg and kneecap.
Edwards, 24, found the defenceless man and punched him in the face and kicked him in the head on Wakefield Road.
Edwards, of Mill Hill Lane, Pontefract, was jailed for six years and nine months after admitting causing grievous bodily harm with intent.
David Hall, prosecuting, said Edwards was in a relationship with a woman for a month and when it ended due to his anger issues she quickly went back to her ex-boyfriend.
Edwards had threatened the man weeks before the attack in Pontefract on July 29, 2018.
The couple were on a night out when Edwards approached them and demanded an apology, which he got and which appeared to calm him down.
But as they left Big Fellas club in Pontefract hours later, Edwards punched the victim and threatened to kill him.
The victim ran off before being cornered in a car park and jumping over a wall with a long drop, breaking his knee cap and femur.
Edwards made his own way around the wall and approached the victim, who could not get away because of his leg injuries.
Edwards punched the victim in the face and kicked him in the head.
Mr Hall said the victim was taken to Pinderfields Hospital in Wakefield where he was found to have a fractured skull, a bleed on the brain and a fractured eye socket.
Edwards was arrested and made no comment in his interviews. His left shoe had the victim's DNA on it.
The court was told that the victim required surgeries and was unable to work for 11 months and walk for six months as a result of the attack.
His legs are prone to numbness and collapse and he takes painkillers, as well as antidepressants.
Phillip Morris, mitigating, said that at the time of the attack his client was suffering from post-traumatic stress disorder after witnessing a friend being seriously assaulted.
The court was told that Edwards had tried to take his own life a month before the attack but his mum had intervened.
Mr Morris said the defendant thought the relationship was serious as they had gone on holiday together and the woman had met his parents, but his PTSD may have clouded his judgement.
Sentencing, Judge Christopher Batty told Edwards: "[The victim] now says he has PTSD by virtue of a serious assault - the irony of that.
"He was particularly vulnerable when you kicked and punched him during a sustained assault. He was a defenceless man."
Edwards was made subject to an indefinite restraining order in relation to the victim and his girlfriend.