Steve McClaren was sacked by Derby County last weekend after the Rams' play-off ambitions were all but sunk by a 3-0 defeat at Brighton.
Derby sit 10th in the Championship table, 10 points adrift of Sheffield Wednesday who currently occupy the final play-off position, and parted ways with McClaren after experiencing "a significant, unexpected and persistent decline in results, team unity and morale."
Former Town manager Chris Powell has also left Pride Park, along with technical director Chris Evans.
Powell had been at Derby since May 2017 in his first role since being sacked by Town in November 2015.
The former Charlton left-back joined the Rams as Nigel Pearson's assistant manager, but took charge of the side shortly afterwards when the ex-Leicester boss was sacked just nine games into the season.
Powell oversaw a win and a draw in the two games he had in the top job, before returning to his previous role when McClaren was announced as Derby manager for the second time.
Rams chairman Mel Morris told the club's official website: "Steve is a great coach, we have very talented players and first class facilities but the heartbeat, commitment, focus and passion has been lacking something fundamental.
"The Brighton game on Friday night was so far from what we expect to see from those wearing a Derby County shirt.
"To ensure we are on the right path, it is important to put the building blocks in place so we can develop a team we can all be proud of. Players should wear the shirt with pride and share, espouse and exude the qualities and values we believe are important to the club, its supporters and the community.
"We need a manager who shares our values and who is prepared to develop the team, staff and processes that will set us on course for a sustainable place in the Premier League. We are less concerned about timescales than we are about getting things right. Of course we would like to achieve this sooner rather than later.
"That manager will of course be given the full support and backing of myself, the board, our executive team and staff to shape and develop the team around those who truly and demonstrably want to be part of Derby County."