Morris was on the lookout for a new club after failing to extend his stay with Chelsea, and a number of clubs made their interest known.
Cardiff were keen on landing the midfielder, but the prospect of staying in The Premiership with Leeds held obvious appeal.
The 24-year-old midfielder has signed a two-year deal with the Elland Road outfit, and will add real steel to The Whites` engine room.
After inking his deal, Morris said: "I am delighted to be joining Leeds United and it is a great move for me.
"Everyone knows Leeds are trying to rebuild and I am looking forward to playing a part in that next season."
