Ayr United have landed another four signings on the eve of the new season.
And boss Mark Roberts has hailed his latest capture as a “huge coup” for the club.
Murphy, 33, played over 400 times at Brunton Park and was also capped by the Republic of Ireland at senior level.
Thrilled boss Roberts told the club website: “When I knew Peter had become available, I jumped at the chance to bring him here.
“I’ve done my homework and everyone you speak to only has great things to say about him.
“He’s a natural leader and just what we’ve needed at the back for a while.
“He has a wealth experience and has even scored a couple of times at Wembley.
Roberts has also added 22-year-old striker Ryan Donnelly on a busy day of dealings at Somerset Park.
Donnelly had previously burst on to the scene at Airdrie two years ago before winning a trial at Wigan under Roberto Martinez.
Marko revealed: “Ryan just needs someone to believe in him.
“He showed the talent he had when he scored nearly 30 goals for Airdrie in one season.
“He has shown me the hunger that he wants to get back to that sort of form.”
Right back Nicky Devlin, who has impressed on trial in pre season, has also been snapped up as United’s squad takes shape.
Roberts said: “Nicky brings pace and is great defensively in one on situations. He will be a real threat going forward.
“Nicky is the type of player who is extremely fit and will be up and down the pitch for 90 minutes.”
Meanwhile, youth star Sean McKenzie has put the icing on his promising pre season by formally agreeing a pro contract with the club.
Roberts confirmed: “Sean is different to the usual small pacey type of striker.