The 32-year-old has moved to the KCOM Stadium on a free transfer after his six-year spell at Sunderland came to an end.
The midfielder, who has made more than 500 appearances in England due to stints at Arsenal, Birmingham City and Sunderland, will wear the number 16 shirt at Hull.
"I'm delighted to be here and I am really looking forward to this fresh challenge," Larsson told Tigers TV. "I had some options to consider, but I felt this was the best move for me to make and I can't wait to get started now."
Larsson becomes Leonid Slutsky's seventh signing of the summer.