Williams returns to Swansea having been on the club's staff under Russell Martin during the 2021-22 season.

The 43-year-old leaves Notts County with the club sitting fifth in League Two.

"As I have said previously, we have undertaken a diligent and detailed process to find our next head coach," said Swansea chairman Andy Coleman.

"I have been fortunate to spend a lot of time with Luke recently. I have looked him in the eye and know that we can trust Luke to be a coach and leader who is aligned with our vision for Swansea City.

"He fits right into the mould of other talented and ambitious young managers who have succeeded here. I am confident our supporters will be excited by and proud of this Luke Williams-led Swansea City team."

Williams' assistant Ryan Harley also make the moves from Meadow Lane back to south Wales, having had a brief spell at Swansea during his playing career.

Notts County's first-team coach analyst George Lawtey is also joining Swansea.

Swansea have agreed a compensation package with Notts County in order to secure the trio's services.

Williams and Harley are set to work alongside Alan Sheehan, who has been caretaker boss since Duff departed, but now reverts to senior assistant coach role.

Luke Williams' Notts County side broke numerous club records last season, including their highest points tally, most wins and most goals scored

Fellow assistant coach Kristian O'Leary and goalkeeping coach Martyn Margetson are also expected to remain at the club.

London-born Williams led Notts County to promotion from the National League in his one full season in charge, the Magpies triumphing in the play-offs after losing out to Wrexham in an epic title race.

Williams is regarded as a high-quality coach who, crucially, is committed to playing the sort of possession-based game Swansea are keen to restore having been criticised for their style of play during Duff's unsuccessful reign.

Duff, who won only five of his 19 league games at Swansea, was dismissed less than six months after being named successor to Martin.

Sheehan then steadied the ship, taking 11 points from seven matches at the helm.

Williams took charge at Notts County in the summer of 2022 and signed a new contract with the club in January 2023.

Having seen his hopes of a professional playing career ended by injury as a youngster, Williams spent time working in a warehouse and as a driver before he began coaching at Leyton Orient and then West Ham.

His big coaching break when he became under-21 boss at Brighton, when Gus Poyet was in charge, before he moved into senior coaching at Swindon Town, where his time as manager ended after relegation to League Two in 2017.

Williams then coached Bristol City's under-23s before working alongside Martin, first at MK Dons and then Swansea.

Luke Williams (right) worked alongside Russell Martin (left) at Swansea and MK Dons

He left in February 2022 with Swansea citing personal reasons, before returning to football at Notts County.

Williams was on Swansea's list of potential replacements for Duff from the outset, although Tottenham Hotspur's senior assistant coach Chris Davies was initially their top target.

But having looked close to taking over at Swansea, Davies opted to stay at Spurs.

That left the Swans to reassess their options, which in part explains why it has taken 32 days for the club to appoint a new boss.

"We know Luke can coach the style of play we want, in part because he was an integral part of delivering it here in training sessions when he was an assistant," said Swansea sporting director Paul Watson.

"Luke's ability is also backed by the data and results. He is a great fit for Swansea City and our ambitions."

Following their 1-0 New Year's Day win over West Bromwich Albion, Swansea sit 16th in the Championship and are eight points adrift of the top six.

Williams' first game in charge will be Saturday's home FA Cup third-round tie against Morecambe, who his Notts County side thumped 5-0 in League Two last week.

He leaves the Midlands club seven points adrift of an automatic promotion spot in the fourth tier.