Gunn, 51, helmed the company's blockbusters Guardians of the Galaxy and Guardians of the Galaxy, Vol. 2, and was poised to direct the third chapter in the sci fi-comedy series. His other credits include two Scooby-Doo movies, Slither and Super.
"The offensive attitudes and statements discovered on James' Twitter feed are indefensible and inconsistent with our studio's values, and we have severed our business relationship with him," Disney Chairman Alan Horn said in a statement to The Hollywood Reporter.
Gunn took to Twitter on Thursday to address the recently resurfaced posts from 2008-09, in which he joked about pedophilia and sexual assault.
"Many people who have followed my career know when I started, I viewed myself as a provocateur, making movies and telling jokes that were outrageous and taboo. As I have discussed publicly many times, as I've developed as a person, so has my work and my humor," he wrote.
"It's not to say I'm better, but I am very, very different than I was a few years ago; today I try to root my work in love and connection and less in anger. My days saying something just because it's shocking and trying to get a reaction are over," he continued.
"In the past, I have apologized for humor of mine that hurt people. I truly felt sorry and meant every word of my apologies," read another post.
"For the record, when I made these shocking jokes, I wasn't living them out. I know this is a weird statement to make, and seems obvious, but, still, here I am, saying it," Gunn added.
"Anyway, that's the completely honest truth: I used to make a lot of offensive jokes. I don't anymore. I don't blame my past self for this, but I like myself more and feel like a more full human being and creator today. Love you to you all," he concluded.
Disney's firing of Gunn came a day after Paramount Television President Amy Powell was ousted for allegedly making racially insensitive remarks during a meeting with colleagues last week -- an act she denied, Variety reported.
"Having spent the past several days conducting a thorough investigation into this matter and speaking to those who were present, our human resources and legal teams came to the same conclusion, and we have made the decision to terminate Amy's employment, effective immediately," Paramount Pictures Chairman Jim Gianopulos told studio staffers in a memo. "While it is incredibly difficult to part ways with a valued member of our community, it is imperative that we uphold our values and ensure that all employees feel safe and included in the workplace."
"There is no truth to the allegation that I made insensitive comments in a professional setting -- or in any setting," Powell said in a statement. "The facts will come out and I will be vindicated."
1. Many people who have followed my career know when I started, I viewed myself as a provocateur, making movies and telling jokes that were outrageous and taboo. As I have discussed publicly many times, as I’ve developed as a person, so has my work and my humor.— James Gunn (@JamesGunn) July 20, 2018