Jody Morris has become Leeds manager Peter Reid's first summer capture after signing a two-year deal with the Elland Road club.
Former England Under-21 international Morris was released by Chelsea in the summer and was available on a free transfer.
He looked set to join Cardiff City but turned them down at the last minute and completed the move to Elland Road after passing a medical on Friday.
Morris is looking forward to the challenge of joining up with Reid's men and helping them come out of their difficult spell.
"I am delighted to be joining Leeds United. It's a great move for me," Morris told the club's official website.
"Obviously everyone is aware that Leeds United are trying to rebuild for the future and I hope I can play my part. I am looking forward to doing so," he added.
Cardiff had been preparing a press conference to unveil Morris, but the player had a late change of heart and instead decided to move to Leeds.
Cardiff owner Sam Hammam was unhappy at his club being "jilted at the altar" by Morris.
Hammam said: "We had agreed every last detail of his contract and he had done 90% of his medical.
"He had done all the scans and X-rays and he was due to do a heart monitor test on Thursday and then there would have been a press conference.
"Then at 2230 BST on Wednesday the agent phones and tells me that Jody had already left the hotel in Cardiff and was on his way back to London."
Morris, who spent seven years at Stamford Bridge, has been linked with Spurs, Blackburn and Portsmouth over the past few months.