Leeds Crown Court today heard how Dean Southern had been drinking with friends in The Ponty Tavern until the early hours of March 12 last year.
One of those friends had become involved in an argument and scuffle inside the pub as staff starting to clear the premises just after 2am.
An off-duty doorman had intervened then and did so again when the same friend became aggressive towards another man outside.
When Southern saw the off-duty doorman intervene, he punched him to the side of his jaw and the man fell to the floor.
Prosecutor Stephen Welch said the victim's jaw had been broken and needed to be reset using metal plates.
He said the man now felt nervous going out and about, had not undertaken doorwork since, and suffered "ongoing pain and discomfort".
Also in court: Man jailed after encouraging sister-in-law to send him indecent images of underage girlSouthern, 26, of St Giles Avenue, Pontefract, admitted one count of inflicting grevious bodily harm.
The court heard he suffered from autism and attention deficit hyperactivity disorder, which had resulted in him never being able to work.
A probation officer advised this meant he was unsuitable for completing an unpaid work requirement, but rehabilitation programmes and curfew could be considered.
Victoria Barker, mitigating, said: "The defendant is extremely remorseful. He accepts that he was heavily intoxicated on that occasion. It was very out of character for him."
She said her client, who pleaded guilty at the first opportunity, also took medication for extreme anxiety.
Also in court: Man snared by paedophile hunters is branded 'dangerous sexual predatorJudge Rodney Jameson QC said he wanted Southern's victim to understand that he would have passed a more significant sentence if other options had been available.
Sentencing him, the judge said: "The fact is, you had a very serious impact on the victim. It has caused him long-term anxiety and concern."
Southern was given a 12 month community order with a 20-day rehabilitation programme and an electronically monitored curfew for six months, from 9pm to 6am daily.