The 26-year-old has penned a three-year deal at Oakwell after the Tykes beat a host of clubs to secure his signature.
Shackell came through the Norwich youth system and played 133 times for the Carrow Road club before moving to Wolves in September 2008. He was soon loaned back to the Canaries before spending the 2009/10 season on loan at Doncaster.
Barnsley boss Mark Robins told the club's official website: "I am delighted to have signed Jason. He has proven himself to be a more than capable Championship player and is a leader on the pitch. I am looking forward to a long and successful working relationship with him here at Barnsley FC."
Shackell added: "I am delighted to be here. I met with Mark Robins and he is really ambitious and wants to push on with Barnsley.
"He was keen to get me in and his enthusiasm, ambition and drive really made this feel like the right place for me. I am ambitious; I want to be pushing on in my career and I feel this is the right place to do that."