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Andrew Breitbart, who died suddenly early this morning at age 43, was notorious for his desire to shake up the political establishment,  a thorn in the side of the liberals and a brazen critic of the mainstream media.

Breitbart vowed his mission was to "expose the counternarrative that has been hidden by those controlling the reins of popular culture."

"This battle is so in my blood," he told GQ in April. "The media is dominated by people who disagree with American exceptionalism-the academic Marxist crowd's worldview-and somebody needed to start taking it on directly. I sleep so well at night taking on these people who I've isolated as the problem."

From posting some of the first semi-nude photos from former Democratic Rep. Andrew Weiner's Twitter account to taking down ACORN and USDA official Shirley Sherrod with selectively edited videos, to accusing Occupy Wall Street of having a "culture of rape," Breitbart was outspoken, untamed and uncensored when it came to conservative commentary and unabashed at inciting controversy.

"Andrew lived boldly, so that we more timid souls would dare to live freely and fully, and fight for the fragile liberty he showed us how to love," Larry Solvo wrote on Big Hollywood, the news aggregate site Breitbart founded in the same vein as the Drudge Report. "We have lost a husband, a father, a son, a brother, a dear friend, a patriot and a happy warrior."

An active tweeter, Breitbart often engaged his rivals and challenged his opponents in 140-character spurts. His final tweet was sent less than an hour before his death.

"I called you a putz cause I thought you were being intentionally disingenuous. If not I apologize. @CenLamar @dust92," Breitbart tweeted.

Breitbart left behind not only his four children and wife Susie, but also a high-profile lawsuit against Sherrod, a former USDA official. Sherrod sued Breitbart for defamation last February because of a video Breitbart edited and posted on his website BigGovernment.com that appeared to show Sherrod, an African American,  supposedly admitting that she discriminated against a white farmer.

The video Breitbart posted was a selectively edited two-and-a-half minute version of Sherrod's 43-minute speech. When the full video emerged, it showed that Sherrod had actually helped save the man's farm, starting a lifelong friendship. Both the NAACP and the White House immediately retracted their condemnation of the video and Sherrod was offered her job back.

Breitbart acted as a mentor and advocate for conservative activist James O'Keefe, who propagated hidden-camera videos of him and fellow activist Hannah Giles supposedly catching the low-income housing and voter registration company ACORN giving advice on how to avoid taxes and get away with child prostitution.

In the selectively edited videos, which Breitbart posted on his websites, Giles dressed as a prostitute and O'Keefe played her pimp while they both attempted to elicit damning responses from ACORN employees. In response to the videos, Congress voted to defund ACORN, essentially putting the community organizing nonprofit out of business.

The ACORN videos, just like the Sherrod video, were later found to be heavily edited. The Government Accountability Office ultimately issued a report showing ACORN had not mismanaged federal funds.

But administration officials and government agencies were only two of Breitbart's many targets. Last May Breitbart was the genesis of the Anthony Weiner scandal, which eventually led to the New York congressman's resignation.

Breitbart was the first to shine a spotlight on the partially nude photos Weiner tweeted of himself.  On May 28 he posted a photo of an underwear-clad crotch, claiming Wiener sent the photo of himself to a Seattle woman. Wiener denied the accusations for weeks, but eventually fessed up to the inappropriate photos and resigned his House seat.

Breitbart was an outspoken opponent to the Occupy Wall Street movement. At the Conservative Political Action Conference earlier this month Breitbart claimed that rape was common in the occupy camps, saying the demonstrators had a "culture of rape."

In speech at the conference, Breitbart denounced the anti-Wall Street protesters as "filthy, filthy, filthy, horrible freaks." Following his speech he got into a face-to-face confrontation with Occupy demonstrators outside the conference, shouting "behave yourselves" at the protesters as police tried to corral them away from the hotel entrance.

Minutes after the news of his death broke around Thursday morning, Rick Santorum and Mitt Romney separately offered condolences.

"Ann and I are deeply saddened by the passing of @ AndrewBreitbart: brilliant entrepreneur, fearless conservative, loving husband and father," Romney tweeted.

Santorum said he was "crestfallen" at the news of Breitbart's death.

"What a huge loss in my opinion for our country and certainly for the conservative movement and the prayers go out to [his] family," Santorum said following his speech in Georgia this morning. "I'm sorry to hear it."