The 22-year-old put pen to paper on a two-year deal after agreeing to join Jack Ross’ side following the expiration of his contract in Paisley.
Dundee United had been hoping to lure the Irishman to Tannadice and looked to be the strong favourites for his signature, though it was reported earlier on Wednesday they’d pulled the plug on any potential move to the City of Discovery with Hibs swooping in.
Doyle-Hayes joined Jim Goodwin’s side last season following his exit from Aston Villa. He played 30 times and earned positive reviews for his performances at the base of midfield, including in St Mirren’s Scottish Cup semi-final defeat to eventual winners St Johnstone. Injury robbed him of the chance to feature in the Betfred Cup semi loss to Livingston earlier in the campaign.
After agreeing to the deal, Doyle-Hayes spoke of his delight at joining last season’s third-place side in the Scottish Premiership.
He said: "After speaking to the manager, I was delighted to get this opportunity.
"Coming into a squad where we’re looking to challenge for medals is definitely something I want to be a part of. Looking at the players here, there’s some unbelievable talents and I’m really looking forward to being a part of that.
"I enjoy both sides of the game. I enjoy digging in and defending and helping the back four, but I also like chipping in with a few assists and maybe a couple of goals if I am lucky."