Beadle, 32, played for the old Scarborough and signed for Athletic towards the end of last term as player-coach.
Manager Darren Kelly said: "I wanted to get Jimmy involved as soon as I came in as manager.
"I've known him for a long time, I trust him and I know how he is thought of at the club, the supporters adore him.
"You need good people in your trenches and Jimmy 100% fits into that category, for me this was a no brainer.
"He will be a great right-hand man, not only because he will be a brilliant link between myself and the players, but also because he isn't a yes man. If he thinks something is wrong he will tell me.
"I hope the fans are happy with the staff I have put together in Jimmy, Ryan Blott and David Brown. It is all about the heartbeat of the club and that is definitely pumping now."