Teenage midfielder Regan Slater has committed his future to the Blades until the summer of 2020.
The 17-year-old, who became the youngest ever Blades goalscorer in a competitive fixture when he netted against Grimsby Town in the Checkatrade Trophy last month, has impressed the coaching staff this term.
Slater, who has also captained the U18s and U23s this season, has signed a two-year professional contract, with the option of a third, with the deal beginning at the end of the 2017-18 campaign when his scholarship comes to an end.
Manager Chris Wilder commented: "Regan is progressing well but signing his first professional contract is just the start for him. There's a lot of hard work to come but it would be great to see another local lad earning a shot at playing senior football for Sheffield United."
Upon signing his deal, Slater echoed Wilder's sentiments and added: "I'm delighted to have committed my long-term future to the Blades, I'm very privileged and living the dream.
"But I know I will have to work very hard in the coming months, before my new contract comes into effect at the end of next season. It was a special moment to score that goal at Grimsby and being around the first-team gave me that taste of what it is like to be a professional footballer."