The 45-year-old was relived of his duties with the club languishing in 18th place in the EFL Championship table after just one win in eight matches.
Having only joined the club in June, Duff leaves alongside assistant coach Martin Paterson. It is understood from the club that fellow assistant head coach Alan Sheehan will take the role of caretaker head coach for an interim period.
Duff’s brief reign began with a seven-game winless streak in the league – including a miserable derby defeat at Cardiff City – before a run of four straight wins lifted his side into the top half of the table.
But they have since taken six points from a possible 24, a worrying run which has cost Duff his job.
The Swans 1-1 draw against Huddersfield proved the last straw for the clubs American owners who had become disillusioned with recent results, whilst sections of the home support made their dissatisfaction clear and the end of the game with the Terriers.
Swansea City chairman Andy Coleman released the following statement:
“This was a very difficult decision and one that was given considerable thought and attention.”
“I acknowledge that there has been a significant amount of change at the club, both on and off the pitch, during Michael’s tenure. I consistently asked for patience as we gave him time to implement his plans and bring the squad together.
“Unfortunately, we have seen neither the results that we expect nor the progress from the squad that we need. I believe it is now in the best interests of Swansea City to make a change of head coach.
“I have the greatest respect for Michael as a person and as a leader. I know how hard he and his staff have worked throughout this season for Swansea City. I want to personally thank Michael, Martin, and their families for the sacrifices they have made on behalf of this club and this city.
“I know that Michael will be successful in his next opportunity and on behalf of the board and the entire club, I wish him and Martin only the best in their future endeavours.
“I understand how important it is to reconnect the leadership of Swansea City Football Club with its supporters. That is one of the primary reasons why I moved here with my family this summer.
“Being present in Swansea matters, but so does taking responsibility. I will learn from the experience of these last several months. My appreciation for how critical the Swansea identity is to this club has grown since the summer and it will be high in my mind as I make the decision on our new head coach.”
[Lead image: Swansea City]