The left-back, who is a product of the Foxes’ Academy, has made a total of 56 Premier League appearances since breaking into their first team during the 2019/20 season.
Upon arriving at Sheff Utd, Thomas told the club's official website: "When United came in a few days ago, it was an easy decision for me. Coming back to playing Premier League football is obviously what I wanted to do. Coming here is a great experience and I can't wait to get started.
"When United came in for me a few days ago it was an easy decision. I can't wait to get started."— Sheffield United (@SheffieldUnited) August 31, 2023
Luke Thomas' speaks to SUTV for the first time since joining on a season-long loan! 🙌 pic.twitter.com/0zFFovfx36
"I had interest elsewhere at the time but then United came along and it was an easy decision like I say - a no-brainer really. I can't wait to get going.
"I think this is a huge moment. Getting game time and getting into the team here is a key thing for me. I want to be playing as many games as possible, especially in the Premier League, my career has gone well so far, I've won a few things, so hopefully I can continue that here."
Known for his quality in both attack and defence, the lively 22-year-old was part of the England side that triumphed in the UEFA European Under-21 Championship earlier this summer.
Sheff Utd manager Paul Heckingbottom expressed his delight with his latest addition, stating: "Luke has got a top pedigree, he's a good young player who also has a wealth of experience at Premier League level.
“What also impressed me was that he was hungry to come in and is keen to get started."