Steve and Marilyn Porter were furious after reading the offensive comments
A housing officer used his Facebook page to make an offensive comment about a Liverpool-born resident.
Ignatius Morgan wrote comments relating to Steve Porter's "Scouse" background on the social network site after a row over problems in his street in Cardiff.
But Mr Porter's wife saw the comments and complained - which led to Mr Morgan being disciplined.
Cardiff council said it had sent an apology to Mr Porter and "appropriate internal action" was being taken.
Mr Porter, a 50-year-old crane driver, was angry about damage to his family cars which he said was caused by children playing ball in the street on his estate at Leckwith, Cardiff.
He had a row with Mr Morgan over the issue and sent him a letter saying all he ever heard was "bounce, bounce, bounce" because the council would not stop children playing ball.
Mr Porter, who was born in Liverpool, was furious when his wife, Marilyn, came across Mr Morgan's personal Facebook page and read offensive comments relating to his "Scouse" background.
The father-of-two printed out the page and gave it to the council, which sent him a formal apology after holding an investigation into the matter.
Mr Porter said: "It is outrageous. I knew straight away that he was speaking about me because I have kept my Scouse accent despite being in Cardiff for nearly 10 years.
"And I had spoken to him on the telephone that morning and even produced the phone bill to prove it.
"He was caught out red-handed - but it just shows what these people are thinking of the people they are meant to be helping. We actually pay their wages with our council tax."
The council said in a statement: "Cardiff council in no way condones this kind of behaviour and we appreciate the seriousness of the comment made.
"A letter of apology has already been sent to the tenant involved and the appropriate internal action is now being taken in line with council disciplinary procedure."
Mr Morgan declined to comment after being approached through the council.
Mr Porter had complained about children damaging his Ford Mondeo and his wife's Mercedes outside their home, a private three-bedroom house, with many council homes around them.
He said: "I've been trying to stop the kids damaging the cars but these council officials have been useless. The kids get away with everything and now we can see why if this is their attitude."
His wife said she was stunned to see what had been written about her husband.
One of the Facebook comments on Ignatius Morgan's page
"It is crazy, arrogant and stupid. He could easily have stopped people looking at his page but he kept it open for anyone to see," she said.
"You think council officials would be there to help but this shows the truth of what he thinks about people who pay his wages."
Mr Porter received a letter from a housing manager apologising for Mr Morgan's "inappropriate remarks" after they had investigated the Facebook page and spoken with him.
The manager apologised on behalf of the housing service and said the housing officer also apologised for the comments.