Mullin joined Wrexham in the summer of 2021, shortly after Hollywood superstars Ryan Reynolds and Rob McElhenney had completed their remarkable takeover. He is now a modern day legend in North Wales and has said of his reasons for heading closer to his Merseyside roots from a spell at Cambridge United: “It wasn't even football to begin with, it was my son. Obviously, it's well documented now but he's autistic, and I've been away in Cambridge for the majority of the season, obviously coming home whenever I could, and I just wanted to be at home with him every night, and Wrexham was the perfect opportunity to do that.
"Ultimately, it was perfect for me, as well in the football sense because it was a club with real ambition, a club going somewhere, a club with aims to get out of the league, but also the one above that and the one above that and to keep progressing. I wanted to be excited going into work every day, and I am. But the most important thing was spending valuable time with my son and my family. Wrexham was the opportunity to do that.”