“Tyrese is someone I’ve liked for a long time,” said Sheffield United boss Chris Wilder.
“As an opposition manager I always saw something in him which made me think I’d like to work with him one day, so I’m delighted to bring him to Bramall Lane.
“You can argue he has a point to prove at the level, but as a staff we have had success in taking on players similar to Tyrese’s situation and then getting the best out of them.
“There’s a desire from Tyrese to step up to the challenge, and we see a really talented player here who is still only 24. It is a partnership which we believe can flourish.”
Campbell’s arrival is the Yorkshire club’s eighth signing of the summer transfer window and third in the space of a week, following loan deals to bring in Harry Souttar and Alfie Gilchrist from Leicester City and Chelsea respectively.