The Republic of Ireland midfielder, who joined the Toffees from Wigan for an initial £13million last week, had a trial with his new club's arch-rivals at the age of 16.
But at the time McCarthy had just broken into the first team at Hamilton and he decided his career would be better served by continuing with them, rather than playing in the Reds' reserves.
Scottish-born McCarthy, now 22, eventually moved south of the border when Wigan moved for him in 2009.
And such was his progress under Roberto Martinez at the DW Stadium that the Spaniard has now ensured he has followed him to Goodison Park.
That means he will now be playing a stone's throw from Anfield - a possible reminder of what might have been - but McCarthy has never regretted his decision.
He said: "There was talk of it (Liverpool). Obviously I went down for a week's trial.
"It wasn't to be, I was too young at the time. I didn't want to move away from home.
"To be honest, the way things have worked out, I am happy."
Everton's deal for McCarthy was completed close to the deadline on what proved a frantic final day of summer transfer activity.
The signings of McCarthy, Gareth Barry and Romelu Lukaku were all announced in the final moments of trading as Marouane Fellaini and Victor Anichebe exited.
McCarthy, speaking as he was officially unveiled as an Everton player at a press conference, was asked about his feelings on that day.
He said: "It was very hectic. At times it goes through your head that it might not happen.
"As time went on, it got to 10.30 at night and I was thinking to myself, 'Is is going to happen or not?'
"Thankfully it did and I'm just delighted to be at such a great club.
"It is a great place to be. Since I heard they were interested I wanted to come here."
McCarthy had no time to familiarise himself with his new workplace after the deal was completed before reporting for international duty with Ireland.
Now he is back with the club and is keen to work hard to justify their outlay.
He said: "It is a price tag and one I need to deal with.
"I am looking forward to trying to prove why I am here.
"It is not going to be easy, we have got a lot of competition for places.
"I am going to give it my best shot and hopefully I can do well."
One of McCarthy's principal reasons for opting for Everton was the opportunity to work with Martinez, under whom he established himself as a top-flight player and won the FA Cup last season.
McCarthy said: "He is a very good manager.
"You can see he likes to play football. It is always pleasing on the eye for people watching.
"It is great to be here with him and hopefully I can stamp my authority on the team and get as many starts under my belt as possible.
"But I have got real competition at the club. There are a lot of big names here. If I need to bide my time, I will bide my time."