Charlton sacked manager Michael Appleton following their 3-2 Sky Bet League One defeat to Northampton at the Valley.
The Addicks’ winless league run extended to 10 matches, with Louis Appere scoring a stoppage-time winner.
An Aaron McGowan own goal and Tennai Watson’s strike had drawn Charlton level after Tyreece Simpson and Sam Hoskins twice put the visitors ahead, but Charlton wing-back Tayo Edun was sent off for a second bookable offence with the score at 2-2.
A club statement on Tuesday read: “Charlton Athletic can confirm that Michael Appleton has left the club with immediate effect after being relieved of his role as head coach.
“The club would like to thank Michael for his efforts during his time in charge.”
Appleton arrived at the Valley in September 2023 after previous spells in charge of Portsmouth, Blackpool, Blackburn, Oxford and Lincoln.