It was in November that Barton directed a petulant punch on the Blackburn Rovers player when it was clear referee Michael Jones was looking away from where the incident took place.
It did not go unnoticed by the Football Association, however, and the 28-year-old was hit with a retrospective three-match ban after video evidence had been studied.
Earlier this week Barton revealed how the matter was "history" and that the Norwegian winger had offered to take him out for a meal after accepting an apology.
Pardew was not in charge when Blackburn travelled to St James' Park, but he feels his influential midfielder has shown in the short time under him that he has made huge strides towards putting a violent past on and off the pitch behind him.
The Newcastle boss admitted the worst side of Barton could have come out during last Saturday's 4-4 draw with Arsenal, when the Gunners cruised in to a four-goal half-time lead.
"I've not felt that in any game he's been involved with me. I wasn't here for the Blackburn game, he let himself down and he has rightly apologised for that. He's been solid in his temperament since I have been here," Pardew said.
"Even last Saturday, Joey's temperament was good because at half-time the old Joey could have thrown a wobbler, but he needed to just concentrate as he did. His reaction might have been different in the past, but it was exemplary this time."
Barton's involvement during the Arsenal visit took an even greater twist four minutes after half-time. It was his crunching but fair tackle on Abou Diaby that led to the Frenchman jumping to his feet and throwing his counterpart to the floor by the neck.
Rather than retaliate, Barton stayed calm and witnessed Diaby then go one step further and push Kevin Nolan in the back. While the Arsenal midfielder was red carded, Barton was allowed to carry on and lead Newcastle to a sensational comeback.
Pardew said: "Joey apologised for that incident with Pedersen and his reaction on Saturday, for me sitting there watching and knowing maybe there was something in the game when the guy got sent off, I thought was first class."
Barton's performances have also been integral to Newcastle's Premier League results so far this season and, had it not been for a wayward past, it is safe to assume he would have been on the fringes of an England recall.
But despite a pretty solid start to life in the top-flight, where Newcastle sit tenth, Pardew knows a place among the elite is far from secure for a further year.
He takes his team to Ewood Park with just a five point advantage over third from bottom Wigan and he knows that there is no room for manouevre on the transfer front now the transfer window has closed.
The arrival of free agent Shefki Kuqi has increased his attacking options following the sale of Andy Carroll to Liverpool on deadline day, but the form of Leon Best looks certain to be crucial between now and the end of the season.
Best has scored four in his last six outings, with one of those arriving in the draw with Arsenal last weekend. He has far from looked the finished article, but Pardew has been impressed by the player's approach since taking over.
"When I arrived there was a mindset at the club that he wasn't going to make it here and when I looked at the stats, no assists, no goals, it didn't bode well," said Pardew.
"So I put the challenge there in front of him. I said 'you'll have to give me something to give me a reason to keep you'. He's managed to get four goals in I don't know how many games."
Best continually knocked on Pardew's door after he had taken over from manager Chris Hughton demanding a chance; it was that determination which earned the forward an opportunity.
But Pardew is also satisfied the £1.5m buy from Coventry 12 months ago does have the ability to succeed, even if he needs to work on adding more to his game.
"When you see him on the training ground, the one thing above all is that he's got a finish," said Pardew. "Sometimes I think he can be a bit sharper in his mind about where things will fall, like Michael Owen who will sniff out a goal, he needs to get that covered a bit better.
"But actually in terms of finishing with the technique to score he's very good. His career at this club will be determined from when he started playing four weeks ago until the end of the season. It's a big part of his career now. At the moment, he's doing OK."