In a YouTube video announcement, Gillespie, who also served as a counselor to former President George W. Bush, said he’s running because “the American dream is being undermined by policies that move us away from constitutional principles of limited government and personal liberty.”

Gillespie talked about his family and how he got his start in politics: as a parking attendant at the U.S. Senate during college.

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“Over the years, with lots of people’s help and advice, I rose from that parking lot to the West Wing, serving as counselor to the president of the United States,” he said.

He also took some early hits at Warner, criticizing his vote for Obamacare and past support for tax increases.

The health care law “kills jobs and costs families the insurance and doctors they like” and should be “replaced,” Gillespie said.

“Sen. Warner cast the deciding vote” for Obamacare, he said. “If I were a Virginia senator, it would not be law today.”

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Gillespie, who has served as chairman of the Republican State Legislative Committee, resigned from that post on Wednesday before he made his Senate bid official, according to a release from the committee.

Warner is a popular senator in a state that’s been trending blue on the presidential level and that elected Democrat Terry McAuliffe governor in November, and taking him on will be no easy task.

But a Gillespie aide told POLITICO Thursday morning that there’s a “big opportunity” to hit Warner on issues such as Obamacare and the stimulus package and on other instances in which the moderate senator voted with President Barack Obama — a strategy that was already apparent in Gillespie’s announcement video.

Warner, who until today had said little about his reelection bid, released a statement saying he was “asking Virginians to rehire” him as their senator.

“I look forward to putting my independent, bipartisan record up against whichever candidate the Republicans nominate at their convention in June,” he said.

Less than an hour after Gillespie’s Web site went live, Warner’s campaign sent out a fundraising pitch to supporters, asking them to pitch in $5 for his reelection bid.

“It’s official,” the incumbent wrote. “As of this morning, we have a nationally known Republican opponent in our race.”

The Democratic Senatorial Campaign Committee wasted no time in attacking Gillespie, with DSCC Deputy Executive Director Matt Canter calling him a “career lobbyist with a partisan history of slash-and-burn politics.”

“When Virginians get to know Ed Gillespie, they won’t like what they see,” he said in a statement. “He was Enron’s go-to guy in Washington, and the paid lobbyist for other special interests whose agenda was out of step with the interests of Virginians. He is a hypocrite on health care reform who was a lead lobbyist for an individual mandate. He was the mouthpiece for the Bush Administration policies that turned a surplus into a deficit and left our economy in shambles.”