Quarry worker Terry Pickering, 34, had been banned from the Queen’s Head Hotel three weeks before the assault due to his “behaviour”.
Chesterfield Magistrates Court heard that during the January 12 incident Pickering appeared at the pub and sat down next to his victim, asking why he was barred.
Prosecutor Becky Allsop said: “He wanted to discuss Covid with (the victim) and started to record him on his phone.”
Ms Allsop said after refusing to leave Pickering then announced “I’m an anti-vaxxer” and he was going to “leave the pub empty”, telling customers they should go elsewhere.
As the pub’s landlord - with help from friends - took Pickering by the arm to escort him out, the defendant swung his fist.
Prosecutor Ms Allsop said: “The blow connected with (the victim’s) head, landing above his left ear, causing pain, discomfort and swelling.”
During a police interview Pickering - who has no previous convictions - made no comment.
Pickering’s solicitor Kirsten Collings said: “He doesn’t challenge the evidence at all - he regrets not walking away.
“He is not an anti-vaxxer - he wanted to talk about Covid - but he appreciates he had too much to drink.
“He regrets the behaviour and since January 12 he has not had a drink.”
Pickering, of Torr Street, admitted common assault.
He was handed a six-month exclusion order not to go to the Queen’s Head, made to pay a £750 fine, £100 compensation, £85 court costs and a £75 victim surcharge.