Jim McGuinness has resigned as Donegal team manager less than two weeks after losing to Kerry in the All-Ireland Football Championship final.
The 41-year-old contacted the Donegal players and the county executive late on Friday night to inform them he was quitting after four successful years.
During his spell in charge, Donegal won three Ulster senior football titles and an All-Ireland SFC crown in 2012.
They lost 2-9 to 0-12 to Kerry in this year's Croke Park showpiece.
It had been thought the Glenties man would take several more weeks to consider his future.
|Jim McGuinness highs|
|1992: Won an All-Ireland Senior Football medal as a substitute with Donegal|
|1998: Played with Ireland's International Rules squad|
|2011: Appointed manager of an underachieving Donegal senior football team|
|2012: Took the county to only their second All-Ireland title success, beating Mayo 2-11 to 0-13|
|2014: Pulled off a shock win over holders Dublin to reach another All-Ireland final|
However, he has now called time on his spell as Donegal boss, having transformed an under-achieving team into one of the top sides in Gaelic football.
Family and work commitments with Scottish Premier League champions Celtic may have swayed McGuinness to leave the post he took up at the start of the 2011 season.
McGuinness lost just four championship games in four years, winning Ulster titles in 2011, 2012 and 2014 and beating Mayo to win the Sam Maguire in 2012.
In a statement, Donegal said: "During his term, Jim brought unprecedented success to our county and made every Donegal person across the globe very proud of their county and their players."
Rory Gallagher, the former Fermanagh player and McGuinness's number two when they won the Sam Maguire in 2012, has been installed as favourite to take over as Donegal boss.