The Scotland international – who has signed a three-year contract – arrived at Turf Moor around 10.30am and the deal was announced shortly afterwards.
Soon after signing the contract the 28-year-old told Sky Sports News: "It's been a whirlwind. I'm just delighted and can’t wait to get started. It's all about working hard and getting into the first team and continuing to play in the Premier League."
On playing more regularly he added: "It's massively important, especially at my age playing every week. I wasn’t going to be involved at Hull. This is a great opportunity for me and hopefully we can stay up."
Reflecting on his departure from Hull and old coach Steve Bruce, Boyd said: "He was great for me. Hull are a great team and the team spirit is fantastic. I wish them all the best."
Boyd began his career with Charlton Athletic before joining Stevenage Borough in 2001.
He went on to make 126 appearances for the club, scoring 31 goals before joining Peterborough United in 2007 where he rose to prominence, helping the club achieve back-to-back promotions to the Championship.
Boyd joined Hull City midway through the 2012/13 on loan, making the move permanent in May 2013.
He featured 29 times in the Premier League for Bruce’s side and was a substitute in the 2014 FA Cup final against Arsenal.
Wishing the player well, Bruce said: "I've been in the game a long time and if all professional footballers were like George Boyd my job would be easy."