The West Wing star's name appeared alongside fellow actors Ed Asner and David Clennon's in a protest against the picture's graphic scenes, which depict U.S. intelligence chiefs waterboarding and humiliating detained prisoners for information in the real-life hunt for terrorist mastermind Osama bin Laden.
The petition urged Academy members to boycott the movie and not give it their vote in the categories for Best Picture and Best Actress for Jessica Chastain.
But Sheen has now spoken out to clarify his stance on the film, claiming he never meant to hurt the film's Oscar chances because he wanted to make a stand against torture itself, not Zero Dark Thirty.
The liberal actor admits, "It's my own fault", explaining to the New York Times that there was a miscommunication about the petition between himself and his assistant.
Instead, Sheen was full of praise for Bigelow and Boal's thriller, revealing he "was very moved and troubled by it". He also applauded the filmmakers for highlighting the methods allegedly used by the C.I.A. to put pressure on terrorists, adding, "(It has) done great, great service to the issue."