O'Keefe became an overnight sensation last year after he and a friend posed as a pimp and a prostitute to secretly record ACORN workers giving them advice on how to cheat on their taxes. The videos led to a massive political backlash and led to the community organizer's being shut down.
"This is not a left or right thing," he said of his stings. "This is about exposing corruption."
O'Keefe turned his camera on Landrieu, the Louisiana Democrat, in January. At the height of the health care debate, O'Keefe and three friends set out to videotape staffers they believed were refusing to field calls from opponents of health care overhaul, after, he says, opponents of the health care bill complained that they could not get through to the Senator's office to criticize her support of the health care reform bill.
Two went undercover dressed as telephone repairmen and O'Keefe carried a camera disguised to look like a cell phone. But before they could film anything, O'Keefe and the three others were arrested Jan. 25 at Landrieu's New Orleans office.
It was an operation some Democrats dubbed "Louisiana Watergate."
"I don't regret what I did...These people have to be investigated," O'Keefe said.
All four pleaded guilty last week to a misdemeanor charge of entering federal property under false pretenses. They were sentenced to community service and probation.
"I'm absolutely going to adjust my tactics so they are a little more careful in the future," he said.
But while O'Keefe has said he is only standing up to power and his mission is to "expose truth and Americans can play judge and jury," critics have said he is a showman and has revised reality for political gain.
O'Keefe has brushed off the criticism, saying he has created a movement of like-minded journalists.
"When you stand up to power, when you stand up to institution, people come after you," he said. "This is not about me. This is about the truth."