McCarthy has signed outright for Championship side Barnsley in a deal said to be worth around £200,000.
“I am absolutely delighted to be here, it's a thrill to get it over the line," he said on joining Barnsley.
"This was the perfect next step for me, to sign for a Championship club, especially one like Barnsley.
"As soon as I came and was walking around the place, you get a real feel and you sense the history of the club so it's a great feeling to sign.
"This was a really easy decision. I went and met the manager and I got a really good impression from him straight away. I felt comfortable and this felt like the right move, I was really impressed as soon as I came through the door."