LOS ANGELES (Reuters) - Conservative activist Andrew Breitbart, an influential voice in Republican circles known for his online media attacks on liberals, died unexpectedly of natural causes in Los Angeles early on Thursday, his family said. He was 43.
Breitbart, the founder of a news website named after himself, was walking late on Wednesday near his Los Angeles home when he collapsed, said his father-in-law, actor Orson Bean.
"He collapsed on the sidewalk and the paramedics were there very quickly and they couldn't revive him," Bean told Reuters in a phone interview.
A friend of Breitbart told Reuters he had a history of heart problems and is believed to have suffered a heart attack.
The brash and outspoken blogger and commentator, who published politically inspired photos and undercover videos and aimed much of his ire at Hollywood liberals, was at the center of several news websites including www.Breitbart.tv, www.breitbart.com and www.biggovernment.com.
Breitbart relished the role he cast for himself as an embattled conservative on the margins of the mainstream media he called "the Complex." Even so, he gained fans as a frequent guest on television news shows.
His work helped generate a number of prominent news stories. Those included undercover videos posted on his website about ACORN, a grass-roots group that offered housing assistance and other aid to the poor, and his role in bringing to national attention a sexually suggestive photo Democratic U.S. Representative Anthony Weiner of New York posted through his Twitter page.
That scandal eventually led to Weiner's resignation last year.
In targeting ACORN, or the Association of Community Organizations for Reform Now, Breitbart posted videos in 2009 by conservative activists who secretly taped employees of the group giving tax advice to a couple posing as a pimp and a prostitute.
The controversy led Congress to deny federal housing funds to ACORN, which disbanded in 2010.
Bertha Lewis, the former head of ACORN, told Reuters she was sad to hear about Breitbart's death. But she said the videos Breitbart posted about ACORN, which helped launch his website in 2009, were selectively edited.
"He really did a lot of damage to a 40-year-old organization that helped millions of low and moderate income folks," Lewis said.
Breitbart faced widespread criticism when in 2010 his website posted a heavily edited version of a speech by U.S. Department of Agriculture official Shirley Sherrod that led to her forced resignation.
Sherrod, who is black, said her bosses at USDA pushed her to resign after Breitbart posted portions of a video in which she seemed to say she had discriminated against a white farmer. But in the full video of the speech that Sherrod gave, she had in fact said race should not matter.
Breitbart mentioned the Sherrod controversy last night in one of his last Twitter messages, in response to a back-and-forth discussion with Web users in which one person suggested he should apologize to Sherrod. "Apologize for WHAT?" Breitbart wrote back.
Breitbart cut his teeth in the freewheeling world of online media as an editor of the Drudge Report, working in Los Angeles. He also worked with liberal blogger Arianna Huffington, playing an early role in the creation of the Huffington Post, which was founded in 2005.
Matt Drudge, founder of the Drudge Report, said in a message on his website on Thursday that he remembered Breitbart as "a constant source of energy, passion and commitment."
"I still see him in my mind's eye in Venice Beach (in Los Angeles), the sunny day I met him. He was in his mid 20s. It was all there. He had a wonderful, loving family and we all feel great sadness for them today," Drudge wrote.
Mickey Kaus, a liberal writer who blogs at website The Daily Caller, said Breitbart and Huffington managed to collaborate despite their political differences.
"Arianna is a tolerant person and he had a personal bond with her so he could forge an alliance with her, he could forge an alliance with me because I'm a Democrat who likes to trash Democrats," Kaus said.
"He was more against the cultural left than against the policy left," Kaus added.
Republican presidential contender Mitt Romney said on his Twitter page that he and his wife were "deeply saddened" by Breitbart's death, calling him a "brilliant entrepreneur, fearless conservative, loving husband and father."
Breitbart was transported to a hospital where he was pronounced dead at 12:19 a.m. on Thursday, said Ed Winter, a spokesman for the Los Angeles Department of Coroner. An autopsy is tentatively scheduled for Friday.
Breitbart was memorialized in a page at Breitbart.tv.
"We have lost a husband, a father, a son, a brother, a dear friend, a patriot and a happy warrior. 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," the memorial page said.
The message said Breitbart "passed away unexpectedly from natural causes."
It was unclear what would become of the editorial team Breitbart created and ran from his headquarters in Los Angeles.
"He was such a larger-than-life person with so much energy and spirit and could do things 24 hours a day, I just don't see how you can replace him," Kaus said.
Breitbart is survived by his wife, Susannah, and their four children.
Additional reporting by Susan Heavey, Tim Gaynor and Mark Hosenball, Editing by Xavier Briand