But former Barnsley man Kyel Reid came back to haunt his former employers as he netted the equaliser with six minutes remaining to clinch the visitors a point and the title.
McCarthy, who made almost 300 appearances for the Tykes during his playing career, was understandably delighted to clinch top spot but is also eager to see his former club avoid the drop and knows three points would have gone a long way to achieving this.
He said: "It is a little bit sombre for me because I hope Barnsley stay up.
"Anyone who has seen me play will like me because the way I fought for the club, and I would do everything for the club I am paid by.
"I hope it is enough for them to stay up though, so it tinges a little bit of sadness.
"But let me make it clear I am delighted to have clinched the title and the players deserve it, and I will enjoy celebrating it tonight."
The former Republic of Ireland coach was also left frustrated with the pitch invasion from both sets of supporters at the end and feels it denied his players the chance to celebrate properly.
"I wasn't best pleased about it, somebody tried to jump on my back and I don't know if it was someone who wanted to celebrate with me or what" he added.
"It was unfortunate, it's mad and it has taken a slight bit of gloss of the achievement.
"I would have liked us to have applauded the fans and celebrate with them but the invasion prevented us doing that."
The visitors, who secured promotion to the Premier League with a 1-0 win over QPR last week, were off the pace for long periods and fell behind to Macken's strike in the 59th minute.
The former Preston striker showed great predatory instinct to knock home from close range at the second attempt, after Daniel Bogdanovic's scuffed shot had fallen kindly to him.
But the Reds were dealt another late sucker punch as Reid found himself unmarked at the far post and coolly brought Matt Jarvis' cross under control before smashing into the bottom corner.
It was a cruel blow for the hosts who could have all but secured their status in the second tier of English football with three points going into the final weekend.
Now, however, it is likely that Simon Davey's side will have to avoid defeat at Plymouth next Sunday is they are to avoid the drop.
Davey said: "It is so frustrating to match a team like Wolves and then throw it away.
"Somebody up there is putting us through the mill at the moment and we have thrown away another two points.
"But we have no-body else but ourselves to blame, so now we need to go to Plymouth and get a result, and I am confident we will do.
"I think the last 10 minutes we stepped off the pace and anxiety came into our play.
Davey added: "We are three points in front of Norwich and I am still confident we can survive.
"It has been an up and down season and it's the first time in three years that it has gone down to the last game but I have always been confident we will be okay."