“We remain committed to progressing our football club, in both the short and long-term, working through a diligent and thorough strategy.
“The appointment of a new head coach is an important one. We will now work and continue our due diligence with the view of making an appointment in the near future.”
Wagner’s assistant Christoph Buhler has also left Carrow Road.
The German was on borrowed time after Knapper replaced Stuart Webber in November and they dropped to 17th in November after a 3-1 home defeat by Blackburn at the end of a run of seven defeats in nine games, and only one win.
But a fine second half to the season saw them win eight straight home games to finish sixth and earn a play-off spot.
They drew 0-0 with Leeds at Carrow Road in the first leg on Sunday but a dire performance saw the Whites cruise to the play-off final, where they will play Southampton or West Brom.
Wagner told BBC Radio Norfolk after the loss at Elland Road: “This is super disappointing, we were very poor and it really hurts.”
Wagner, who led Huddersfield to promotion to the Premier League in 2017, was appointed in January 2023, replacing Dean Smith, and eventually finished 13th in the Championship last season.
He failed to reference Knapper during a post-game press conference following the final day 1-0 defeat at Birmingham, despite praising his predecessor Webber for his support.
