The Blades have paid Cardiff City an undisclosed fee for goalkeeper Simon Moore.
Moore has put the finishing touches to a three-year deal which has delighted Blades boss Chris Wilder.
The Blades boss commented: "I've said for a while, competition is key and Simon will provide that in the goalkeeping department. We've tracked him for quite a while, done due diligence with people that have worked with him. We have taken our time to get the right one.
"Simon is a good age, he's got experience. We've got good value too, it is a good deal for Sheffield United and now it is up to him to produce the performances we know he is capable of."
Sandown-born Moore played in non-league for Brading Town and Farnborough, either side of a spell within Southampton's Academy.
But it was at Brentford where the 26-year-old really made his name. Having signed in August 2009, Moore was forced to be patient in waiting for his debut almost a year later when he came off the bench to replace then Arsenal loanee Wojciech Szczęsny.
Moore's breakthrough at Griffin Park came in 2012/13, making 52 appearances in all competitions as Brentford narrowly missed out on promotion to the Championship, losing the play-off to Yeovil Town at Wembley.
In July 2013, Moore joined Cardiff City for an undisclosed fee and penned a four-year deal. But having failed to displace David Marshall, Moore ended the campaign on-loan at Bristol City.
Moore, who represented the Isle of Wight in the 2009 Island Games, went on to make a further 24 appearances for City over the course 2014/15 and 2015/16 seasons.