The court heard how just after midnight on 26 July 2020, following an altercation Gard followed the 24-year-old victim down the High Street and punched him, causing him to fall and hit his head on the curb.
The victim was rushed to hospital where he was placed into an induced coma, and was not expected to live.
Despite this initial prognosis, he has made some recovery but will likely be permanently disabled as a result of his head injury.
Gard handed himself into officers later that day.
He has been sentenced to two years in prison.
Detective Sergeant Dan Hunt said: “This act of violence very nearly resulted in the death of a man. Due to Gard’s actions, this young man’s life was changed in an instant.
“The victim will likely be permanently disabled, and he and his family are living with the consequences of this incident every day.
“A single and a split second decision can cause lasting damage to people’s lives. The message to take away from this is, one punch can be devastating. If you find yourself getting involved in a confrontation or argument, stop, think about the potential consequences, and walk away.
“We would encourage everyone to think about how easily a momentary decision can affect the rest of your life and potentially others.
“I hope that this sentence provides closure to the victim of this violent and distressing attack, as well as reassurance to the wider public that offences like this one won’t be tolerated.”