The 26-year-old has agreed a deal running until January 23 after spending much of the summer training with the Millers without a contract. His perseverance has impressed head coach Alex Bruce, who believes the former England Under-21 international has earned the opportunity through his commitment.
“I'm really pleased he's a Rotherham player,” Bruce said. “He deserves the contract. He's worked really, really hard with us since pre-season.”
Williams continued working with the League Two club after initially leaving without an offer, hoping to convince the coaching staff that he was ready to return to competitive football. Rotherham’s decision also comes amid defensive injury problems, with left-sided defender Ewan Otoo facing a prolonged spell out.
Bruce praised Williams’ attitude during his time at the club, highlighting the effort he had put in despite being unpaid.
“He's shown a great attitude every day, he's shown an appetite and a hunger just to play. And he's had a tough few years.”
The manager added that he did not want to hand out contracts without good reason, but felt Williams’ determination justified the decision.
“I'm really pleased to get him in and give him the opportunity to get his career to kickstart.”
Williams came through Manchester United’s academy and made 51 first-team appearances after breaking into the senior side under Ole Gunnar Solskjaer in the 2019-20 season. He subsequently had loan spells at Norwich City and Ipswich Town before leaving Old Trafford in 2024.
His attempt to rebuild his career at Hull City proved short-lived. He joined the Tigers in August 2025 after a lengthy period away from professional football, but made only one brief substitute appearance before leaving by mutual consent in February 2026.
Williams’ progress had also been disrupted by a dangerous-driving conviction. In May 2025, he received a 14-month prison sentence suspended for two years following a high-speed crash in Cheshire in August 2023. He was also banned from driving for three years and ordered to complete 180 hours of unpaid work.
In an interview last year, Williams spoke about his regret and his determination to change the perception of him.
“It was a proper wake-up call. Since then it was about building and changing a reputation that I had and that’s not me,” he said.
“I look back at myself now and think what an idiot I was. That is not what an athlete does, it’s not what a footballer does, it’s not what a grown man does. It’s stupid stuff.”
He also described how much he missed the routine of being part of a team and his desire to return to the pitch. Rotherham have now given him that opening, with Bruce keen to see him turn his work on the training ground into a fresh start in League Two.