Jason Simpson, of Braidwood Road in the town, pleaded guilty to three charges relating to the incident when he appeared at Kilmarnock Sheriff Court in December.
The 34-year-old admitted assaulting a man and butting him on the head, shouting and swearing at police officers, and having cocaine in his possession on May 25, 2024, in Kilwinning Main Street.
The court heard how Simpson approached another man outside the pub at around 12.45am and headbutted him, causing the victim to fall to the ground.
Simpson then attempted to follow witnesses to the incident but was prevented from doing so by others.
CCTV operators notified the police, who traced Simpson and placed him in handcuffs. He was searched and two plastic bags of white powder were found which contained three grams of cocaine.
He was taken to a police vehicle, and shouted and swore at police officers.
Defence solicitor Peter Murray told the court that Simpson was currently unfit for work and in receipt of benefits, due to a separate “horrific attack” that was being treated as attempted murder by police.
On the May 25 incident, Mr Murray said: “He had been on a night out with friends and consumed three alcoholic drinks before becoming unwell.
“He has no recollection of incidents after and says his drink was spiked, but he is not using this to justify his actions.
“He has shown genuine remorse and has apologised to the complainer for his behaviour. He knows this offence is serious as it is an unprovoked assault on an individual.”
Sheriff Morag Fraser handed Simpson a structured deferred sentence, with a review in three months.
A structured deferred sentence is a program that provides social work support to people who have been found guilty of a crime but are not yet sentenced.
The goal of an SDS is to help people avoid reoffending by addressing the underlying issues that led to their crime.