"As a young man, I made a mistake that I deeply regret and for which apologies may still not be enough,” he said in a statement sent to ABC News. "After I moved with my wife to Los Angeles from New York City in 2001 shortly after 9/11, I told people that I was in one of the World Trade Center towers on 9/11. It wasn’t true."
After the foundation of his story came crashing down, Rannazzisi, 37, took to Twitter to address his mistake and say, "to the victims of 9/11 and to the people that love them--and the people that love me--that I ask for forgiveness."
His fellow "League" co-stars also took to Social Media to address their concerns, but support their friend and co-worker since the show began in 2009.
"I believe that he made an idiotic, hurtful mistake he felt he could not outrun," co-star Mark Duplass wrote. "But I also know for certain that he is a good friend."
Duplass's wife and show co-star, Katie Aselton, also responded.
FX, the network that airs "The League," did not immediately respond to a request for comment.
Meanwhile, Comedy Central released a statement, saying the network was also disappointed. Rannazzisi has a special "Breaking Dad" airing on Saturday on Comedy Central.
"We just learned about this last night. We are very disappointed to hear about Steve's misrepresentations and are currently determining how we will move forward," the network said.
Rannazzisi posted the full statement on Facebook: