Sharp, who completed a move to Bramall Lane late on Saturday night, has signed a two year contract with the Blades, where he will be reunited with Nigel Adkins, who he played for at both Scunthorpe and Southampton.
Sharp returned home early from Leeds tour of Austria and Norway to open talks with the Blades and the deal was sealed after the striker passed a medical on Saturday morning. The Blades have paid an undisclosed fee for his services.
Sharp who has spent two previous spells at Bramall Lane made 35 appearances for Leeds but only scored five goals with his last coming their 2-1 home win over Ipswich Town in March. He will probably be best remembered for his last-minute winner away at Huddersfield in January 2015.
However, Sharp admitted his time at Elland Road did not go “as well as he would have liked”.
He said: “It goes without saying a massive thanks to the Leeds fans who believed and supported me whenever I pulled the famous white shirt on.
“Sadly things haven’t gone as well as I would have liked them to.
“I’ve always wanted to play for Leeds and will have fond memories of my short time there. Good luck for the season and thank you.”
On his move to Sheffield United, the boyhood Blades fan added: “It’s a pleasure to be back working with a manager [Nigel Adkins] who believes in me and of course it’s fantastic to play for the club I’ve grown up supporting.”