Washington entrepreneurs Ted Leonsis and Steve Case have assembled a $450 million investment war chest with the aim of rebuilding a start-up culture in the region that once gave rise to the company that made them rich, AOL.

For all its success, the Washington economy has a reputation for lacking the financial growth engines essential to entrepreneurial capitals such as Silicon Valley, New York and Boston.

The region has been buoyed by a boom in federal contracting. But outside the business of the U.S. government, efforts to stir up a swashbuckling business ethos that spawns cutting-edge technology enterprises have come in fits and starts.

Now the two friends and business associates who rode AOL’s stock to dizzying heights and then watched it crash have ­established the Revolution Growth Fund, which will file papers with the Securities and Exchange Commission on Thursday after eight months of raising capital.

At $450 million, which is a significant amount for a first-time effort, the fund signals that the two entrepreneurs are putting their money — around $75 million between them — to work in an attempt to reignite the same culture that gave rise to local innovators such as MCI and AOL.

The late 1990s turned the Dulles corridor into a boomtown, filled with newly minted millionaires asking one another how much their net worth had increased that day. They bought big cars, flew their own airplanes and held lavish Christmas parties. The area quickly became home to scores of technology start-ups, and Washington became known as a hotbed for the emerging online world. Case was hailed on the cover of magazines as the next great tech visionary.

That all changed when the dot-com bubble burst in 2000, and the region has spent the past decade trying to rebuild its technology sector. MCI is long gone. AOL left for New York. And Case became associated with AOL’s disastrous merger with Time Warner in 2000, now viewed as one of the worst deals in business history.

“We know they are both brilliant operators, and we know that they have each made some reasonably good investments,” said Michael K. Farr, president of Farr, Miller & Washington, a D.C. money manager. But, he added, “it’s going to be a great challenge even for Case and Leonsis to differentiate themselves in a very competitive market.”

Allen Morgan, a Bay Area investor who has invested with both Leonsis and Case previously, said the pair have more than just money. They are “super-connected,” said Morgan, who predicts the fund will be very attractive to entrepreneurs.

Since the Time Warner merger, Case and Leonsis have reinvented themselves.

Case, 53, is one of the business community’s representatives on President Obama’s Jobs Council. He runs an array of businesses from his 10th-floor office overlooking Rhode Island Avenue.

Leonsis, 54, who sits on the board of American Express, has become a well-recognized business and sports figure. He owns Verizon Center, and his NBA Washington Wizards and NHL Washington Capitals are money losers, although the Capitals have routinely sold out games in the past few seasons.

Case and Leonsis said they hope their new fund will disrupt the trend of technology start-ups turning to Silicon Valley.

“We want to make it easy for companies to get started here, and particularly to stay and expand and grow while being headquartered here,” Case said in an interview, adding that the fund will look for prospective investments up and down the East Coast.

Case and Leonsis, along with a third partner, Donn Davis, 49, who also worked at AOL, said they will target a new category that they call “speed-up capital,” which is designed to expand companies worth $100 million into ones worth $1 billion or more.

The two executives said Washington has the “angel” investors who can provide the $10,000 or $100,000 in seed money that gets a company from an idea to a small one- or two-person operation. The region also has venture capital firms, such as New Enterprise Associates, that can provide the $1 million or so that sparks a company into life.

But to go from 50 employees to 1,000, companies need big batches of cash — $25 million or more.

When LivingSocial, based in the District, needed a big infusion of cash, it looked west for funding. The Revolution Growth Fund will try to fill that role. That’s different from the Carlyle Group, whose traditional business is to buy large, established companies, improve them and sell them at a profit.

“We want to take off the table the capital issue,” Case said.

Revolution Growth, which will be based in the offices of Case’s holding company in Washington, said it will invest in about 10 to 12 consumer technology companies over the next five years. All investment decisions must be unanimous among the three partners.

“Our goal is to make big investments . . . and really work closely with the entrepreneur to help that company grow,” Leonsis said. “We want to take companies from niche-y to mass.”

Case and Leonsis’s biggest recent success was Revolution Money, an online payment system. The pair sold it to American Express in 2010, earning a more than threefold return on their money.

Case’s high-profile Revolution Health, which financed medical clinics at big retailers and offered online health-care information to consumers, did not fare as well, and he merged it with Waterfront Media in 2008. He also merged his Flexcar rent-by-the-hour company with Boston-based Zipcar in 2007.

Leonsis is an investor in Group­on, and Case has invested in its rival, Washington-based LivingSocial. LivingSocial is run by Tim O’Shaughnessy, son-in-law of Washington Post Co. Chairman Donald E. Graham.