The 28-year-old has agreed a three-year deal with the Potters after deciding to leave Sunderland on a free transfer.
"I'm really pleased to bring Phil into the club," Hughes told the club's official website. "He's a player of great Premier League experience who I think will bring added quality to the squad.
"He has plenty of qualities that will improve us and help move the football club forward to where we want to be. Phil was genuinely excited to join and I'm delighted to bring him in as his personality and desire will shine in the dressing room."
Bardsley made 200 appearances at Sunderland over six years at the Stadium of Light.