Paddy Tally has left his post as Down manager after three years in charge, the county board confirmed in a statement on Thursday night.
A proposal to extend Tally's three-year term until 2022 failed to attract enough support from county board members this week.
Down exited the 2021 championship after a 16-point defeat to Donegal in their Ulster first-round match in Newry in late June.
However, Tally did lead Down to preserving their Division 2 status, after a seven-point victory over Laois in the relegation play-off.
In 2020, they overcame Fermanagh in the Ulster quarter-final and appeared destined for an Ulster final appearance until they were dramatically overhauled by Cavan in the second half of their semi-final in the Athletic Grounds.
On his departure, Tally said his tenure had brought challenges but that the team had "achieved more than many predicted".
"Nowadays, it takes a bigger team to support a team," he said. "The last three years have brought unexpected challenges to each and every one of us.
"Despite everything, I am confident that Down GAA has much reason to be hopeful. With the team, we secured their position in Division 2 and continued the process of rebuilding.
"We have not achieved as much this year as we would have wanted, but in maintaining our league status, the team perhaps achieved more than many predicted, and I hope they can push on from here.
"I am very grateful to the players with whom I have worked in the last three seasons and to their clubs and families.
"I will always have a connection and an abiding personal respect for Down GAA."