Steven Campbell (45) shoved James King so hard he slumped to the ground with a fractured hip.
Mr King had gone to help a young woman who complained about Campbell parking over three spaces at a McDonald’s in Kirkintilloch, East Dunbartonshire.
The thug assaulted the OAP after shouting at him: “F*** off – I’m not moving for anyone.”
Mr King had been super-fit before the attack – going to the gym three times a week and still working as a delivery driver.
But, Glasgow Sheriff Court heard he is now unable to do that - and states he is a “different person” after his ordeal.
Campbell, of Hamilton, South Lanarkshire, was jailed for 20 months by sheriff John McCormick after he pled guilty to assaulting the OAP to his severe injury.
The assault happened after Mr King left the McDonald’s restaurant with his wife last December.
He noticed the diner’s assistant manager was beeping the horn of her car to get Campbell to shift his ice cream van.
Prosecutor Lucy Adams said: “She told Mr King she was trying to park her vehicle, but was being prevented from doing so.”
The pensioner stepped in and asked an “irate”Campbell to move.
But, he yelled back: “What’s it going to do with you? Campbell then leapt out his vehicle, ranted and swore before stating: “Do you know this old c***. Is he related to you?
“F*** off you old c***. I’m not moving for anyone.”
Miss Adams said Mr King and the woman were “terrified”.
The fiscal added: “He approached Mr King and – with both hands – pushed him on the body with force.
“Mr King fell backwards onto the ground and Campbell got into van and drove away.”
The injured pensioner was helped back to his feet and was initially able to go home.
As police tried to trace Campbell, Mr King’s daughter told officers her dad was still in “severe pain” days later.
It emerged he had suffered a fractured hip. The court was told the incident has left him badly affected.
He was tearful during a phone call with prosecution staff earlier this month.
Miss Adams: “He described himself as ‘a different person now’. He stated the incident has upset his whole family.
“He described leading a very active life even in his senior years. He went to the gym two to three times a week to keep fit.
“He also worked part-time for the last 10 years carrying out deliveries for a local pharmacy’
“He is now not able to go to the gym and has given up his employment.”
Mr King takes painkillers to help sleep at night, is “nervous” on his feet and needs a walking stick for the first time in his life.
The court heard when Campbell was held by police, he stated: “I can only apologise.”