Fisher spoke out on Twitter shortly after “forcefully [retracting]” his past praise of Whedon.
Whedon’s alleged “on-set treatment of the cast and crew of Justice League was gross, abusive, unprofessional, and completely unacceptable,” Fisher tweeted on Wednesday.
He added: “Accountability > Entertainment.”
The Independent has contacted Whedon’s representative for comment.
Fisher portrays Victor Stone/Cyborg in Justice League, which was released in 2017 to mixed reviews.
Zack Snyder was originally tasked with directing duties with Justice League but had to drop out of the project due to a death in his family.
Whedon was brought in for what has been described as extensive reshoots.
On 29 June, Fisher first publicly changed his stance on Whedon when he shared an archive video of himself calling Whedon a “great guy” and giving a positive mention to his involvement in the film.
Along with the clip, Fisher tweeted: “I’d like to take a moment to forcefully retract every bit of this statement.”