Chris Wilder has spoken of his delight after strengthening his attacking options with the loan signing of a Premier League striker.
Gary Madine, who won promotion from the Championship with Cardiff City last season, has joined until the end of the season, United can confirm.
Speaking after completing the deal, boss Wilder commented: "I sign the players for this football club and I try and get as many right as possible. Generally we've got things right and I'm more than positive, more than happy with this signing.
"Gary gives us a physicality at the top of the pitch, tactically he gives us something different, which we'll need in the second part of the season.
"If you ask any of our centre-halves for their opinion of playing against Gary Madine, they'll all say the same, he's a tough boy to play against. He is physical and technically very good too, hopefully he'll be able to get on the end of some of the crosses we put in.
"I'm looking forward to working with Gary, he's won promotion with Bolton and scored goals there. And if anyone knows anything about a striker it's our old manager (Neil Warnock), he took a punt on him last season and was part of the Cardiff squad that went up."
Madine, 28, added: "There were other teams interested, but believe it or not when I knew Sheffield United was interested, I was buzzing and jumped at the chance. I've played with some of the lads and against them too, I was dying to make the move happen.
"Some people have this perception I don't like Sheffield United, but that's not true. I've had over 20,000 supporters booing me when I've played here before, it's an intimidating place to come and some players would crumble.
"But I've always thought I wouldn't mind being part of that and it is certainly a club on the up, one who play some excellent football."
Having been released by Middlesbrough as a youngster, Madine progressed through the youth ranks at Carlisle United and made his debut as a 17-year-old. He scored 22 times in 85 appearances during his time at Brunton Park and in January 2011 joined Sheffield Wednesday on a four-and-a-half-year deal for an undisclosed fee.
The powerful marksman then impressed Blades boss Wilder and his backroom staff during his time with Bolton Wanderers, scoring for them in a 1-0 victory at Bramall Lane in December 2017.
In January 2018, Cardiff boss Warnock decided to make Madine a multi-million-pound signing to help propel his Bluebirds towards the Premier League and the marksman came off the bench at Bramall Lane last April as City snatched a point, subsequently winning promotion.
He completed a medical over the weekend and watched United's FA Cup encounter against Barnet.
Madine is the second Premiership player through the Bramall Lane doors already in this transfer window, following Kieran Dowell, who has signed from Everton until the end of the campaign.