Portsmouth have sacked Kenny Jackett following their defeat in the Papa John's Trophy final against Salford City.
Pompey lost on penalties to their League Two opponents, which followed three successive defeats in League One against Sunderland, Northampton and Doncaster.
The Fratton Park side sit seventh in the third tier, two points outside the playoff spots.
Chief executive Mark Catlin said: “Portsmouth Football Club would like to place on record our sincere thanks to Kenny for the work he has done during his near four-year spell at the club and we all wish him well for the future.
“It has been an emotional past few weeks for everyone associated with Pompey and we now begin the process – which will be as short as possible – of appointing someone who we believe can give us the best chance of finishing inside the top six.
"These talks begin today.”
Jackett, who has previously taken charge of Watford, Swansea, Millwall, Wolves and Rotherham, joined Portsmouth in 2017.
He won the Papa John's Trophy in 2019 as Pompey beat Sunderland in the final and led them to finishes of eighth, fourth and fifth in League One.
But successive playoff defeats to Sunderland and Oxford mean Pompey failed to get out of the third tier under Jackett's stewardship as they look to climb the leagues having been in the top flight as recently as 2011-11 before financial issues took their toll.
