(CNN) – UPDATE: National Public Radio CEO Vivian Schiller resigned Wednesday, according to the organization's website. This comes the day after tape was released of an NPR senior executive slamming the tea party and saying NPR would be better off without federal funding.
The conservative activist responsible for producing an undercover video showing a National Public Radio senior executive slamming the Tea Party as "racist" and "scary" is speaking out about why he went after the organization.
Late Tuesday evening, the executive in question, Senior Vice President for Fundraising Ron Schiller, issued an apology and said that his already-announced resignation would be effective immediately, instead of in May as planned. Schiller had announced last week that he was leaving NPR for a job with the Aspen Institute.
Filmmaker James O'Keefe said the idea for the sting stemmed from an incident in October when NPR fired analyst Juan Williams after he said he got scared when people wore Muslim garb on airplanes.
"My colleague Shaughn Adeleye who posed as one of the members of the Muslim Brotherhood was pretty offended with what happened with Juan Williams and he suggested looking into NPR after that incident back in the fall," O'Keefe said to CNN Correspondent Brian Todd on Tuesday.
"My other colleague Simon Templar came up with the idea to have a Muslim angle since Juan Williams was fired due to his comments. So we decided to see if there was a greater truth or hidden truth amongst these reporters and journalists and executives."
Juan Williams has since been hired full-time by Fox News.
O'Keefe gained notoriety for posing as a pimp and secretly taping damaging conversations with employees at the Association of Community Organizations for Reform (ACORN). He was also involved in a failed plot to embarrass a CNN correspondent on hidden cameras.
Schiller and another NPR executive are shown on the video having lunch with potential NPR donors, who were really working for O'Keefe undercover. In the video, they pose as representatives of a Muslim organization that is considering making a $5 million donation to NPR.
Late Tuesday evening, Schiller issued an apology through NPR.
"While the meeting I participated in turned out to be a ruse, I made statements during the course of the meeting that are counter to NPR's values and also not reflective of my own beliefs," Schiller said in a statement. "I offer my sincere apology to those I offended. I resigned from NPR, previously effective May 6th, to accept another job. In an effort to put this unfortunate matter behind us, NPR and I have agreed that my resignation is effective today."
Earlier, an NPR spokeswoman condemned Schiller's remarks.
"The comments contained in the video released today are contrary to everything we stand for, and we completely disavow the views expressed," said NPR spokeswoman Dana Davis Rehm. "NPR is fair and open minded about the people we cover. Our reporting reflects those values every single day – in the civility of our programming, the range of opinions we reflect and the diversity of stories we tell."
Rehm also decried Schiller's statement that NPR would be "better off without federal funding," in the statement – her second released since reports of the undercover video surfaced.
"The assertion that NPR and public radio stations would be better off without federal funding does not reflect reality. The elimination of federal funding would significantly damage public broadcasting as a whole," Rehm said.
– CNN's Brian Todd and Dugald McConnell contributed to this report.