The 27 year-old utility midfielder has moved to Craven Cottage to help bolster the ranks of Martin Jol's squad ahead of the coming campaign
The 27-year-old has signed a three-year deal with Martin Jol's side with an additional year's option after telling former boss Martin O'Neill that he wanted to seek a move further south to be closer to his family.
After bringing an end to a six-year association with the Wearside club, Richardson declared himself delighted to be at Fulham and that he couldn't wait to get going.
"I’m delighted that my transfer to Fulham has been completed and now I’m eager to start training for my new club straight away and pulling on the white shirt for the first time," Richardson told the club's official website.
With Moussa Dembele having already left the club this transfer window to join Tottenham and Clint Dempsey widely expected to leave Craven Cottage before the end of deadline day, manager Martin Jol was pleased to add some depth to his midfield.
"Kieran is a proven top-level player, who has the versatility to play a number of positions," Jol explained.
"He will bring all-round quality which will add strength to our squad and I’m confident that he will adapt well to our style of football, and make an impact for us."
Richardson has represented England eight times at international level, scoring twice and is capable of operating at left-back, on the wing or in the middle of midfield.