James V. Kimsey, co-founder of America Online, in 1995. He donated millions to the Kennedy Center and to other charitable and civic causes. (Dan Murano/The Washington Post)

James V. Kimsey, a flinty former Army Ranger and Washington businessman who teamed with a young marketing expert named Steve Case to start America Online, the early dial-up service that put millions of people on the Internet and informed them, “You’ve got mail,” died March 1 at his home in McLean, Va. He was 76.

The cause was melanoma, said his son, Mark Kimsey.

If not as widely known as Case, Mr. Kimsey cut a distinctive and influential path through Washington’s business elite. As an entrepreneur, he played a pivotal role in making AOL one of the region’s great wealth creators, spawning the fortunes of Case, Washington sports mogul Ted Leonsis, and numerous other decamillionaires.

Mr. Kimsey, who sat on several local boards, was far from the button-down, executive-suite stereotype. To his admirers, Mr. Kimsey was Washington’s John Wayne, a gruff, plain-spoken man’s man, a Vietnam War veteran who held court at one of the area’s watering holes and preferred the company of four-star Army generals.

He plowed his fortune into philanthropic and civic endeavors, from his failed bid to bring a Major League Baseball franchise to Washington in the 1990s to the millions of dollars he lavished on the Kennedy Center.

James Kimsey and Cardinal Theodore McCarrick at a reception at the Kennedy Center in 2002. (Michael Lutzky/The Washington Post)

He was part of a local Catholic business brotherhood that included sports mogul Raul Fernandez and the investor Joseph E. Robert Jr. They helped fund one another’s charities, notably making sizable donations to Robert’s politically incorrect “Fight Night,” which raises money for children’s education.

Case, AOL’s former chairman, said his mentor stuck by him when investors called for Case’s head during the start-up’s early days. “He was very loyal and supportive of me early in my career,” Case said Tuesday.

Mr. Kimsey, a West Point graduate, came back to his native Washington around 1970, began working as a stockbroker and gathered $2,000 to start a lucrative sideline in downtown bars, among them one called Bullfeathers.

A fellow alumnus who became a venture capitalist introduced him to a small technology company in the 1980s called Control Video, which was trying to provide online computer games to Commodore II users.

The company was struggling when Case, 25, a former manager of new-pizza marketing at Pizza Hut, met a partner of Mr. Kimsey’s at a consumer electronics show in Las Vegas in 1982.

A year later, Mr. Kimsey and Case were working at Control Video, trying to stabilize the company. Mr. Kimsey was founding chairman and chief executive; Case was the executive vice president.

“It was a little bit of having the right team,” Case said Tuesday. “Jim focused, because he was older and more credible, on raising money. He helped build the board and build the investor group. I focused on the marketing and strategic partners.

“Jim really played a pivotal role in taking an idea that seemed far-fetched to most venture capitalists,” Case added. “Without Jim, AOL would never have happened.”

After some restructuring and a new round of financing, Control Video was reborn in 1985 as Quantum Computer Services. At the time, Case’s job was to sell Quantum’s new online service, Q-Link.

When Q-Link went live at 6 p.m. on Nov. 1, 1985, only 24 users logged on during the first 14 hours. From there, it grew fast.

Quantum decided to pivot from Commodore II to another rising technology star, Apple Computer, and its Apple II PC. But the relationship cratered in 1989 over who controlled marketing and other matters.

Mr. Kimsey and Case decided to reinvent Q-Link. They held a contest among employees to come up with a new name for the online service. Case thought of Online America, flipped the words around and declared himself the winner.

Q-Link soon became Vienna, Va.-based America Online, a Mac-only online service that offered games, email, chat rooms and some news articles.

Mr. Kimsey thought he would only stay a few years in an entrepreneurial role, but he ended up serving as AOL chairman for a decade before stepping down in 1995. The company went into a long decline starting with the infamous 2000 merger with Time Warner, which decimated the stock of both companies.

AOL was spun off from Time Warner and is owned by Verizon. The media and content company is based in New York and owns websites such as the Huffington Post, TechCrunch and Engadget.

Mr. Kimsey became a behind-the-scenes power broker and enjoyed his fortune — at one point, he was worth $1 billion. His signature Bentley, driven by his close friend and driver, Kissinguer Mom, was a fixture around the city, whether it was parked outside the Palm restaurant, the Jefferson Hotel, a downtown nightclub or the fundraiser-of-that-week.

Mr. Kimsey was frequently seen in the company of beautiful, often-younger women. He was linked with boldfaced names such as Jordan’s Queen Noor, the U.S.-born widow of King Hussein.

He lived in a 60,000-square-foot, $45 million home in McLean, with an infinity-edge pool overlooking the Potomac River and an adjacent Frank Lloyd Wright-designed guest house.

“I think one of the best things I ever did was let Steve run the company,” Mr. Kimsey told The Washington Post in 1995. “Today that one decision to get out of the way makes me look like a genius.”

James Verlin Kimsey was born in Washington on Sept. 15, 1939. He grew up in a poor Irish family but he was driven and bright enough to develop the early nickname “Lightbulb.” He was tossed out of Gonzaga College High School in his senior year for being, as he told Newsweek, “a wisea--.”

He finished in 1957 at St. John’s College High School, where the Kimsey Science and Technology Center is named for him. After graduating in 1962 from the U.S. Military Academy at West Point, N.Y., Mr. Kimsey became an Army Ranger and began two tours of duty in Vietnam starting in 1965.

Taking over a command in Duc Pho, a rural district on the south-central coast, he finished building an orphanage that the previous troops had begun. He would visit the orphanage and continue to fund it and a school there for decades.

“I thought it was critical to interact with the Vietnamese on a real level,” Mr. Kimsey told The Post in 1995. “There was such a xenophobia and we were so insulated from them.”

His immersion into business was not always smooth. In 1975, while working as a stockbroker, he was barred by the Securities and Exchange Commission from associating with any investment company for a minimum of five years for allegedly participating in a scheme that misled investors.

But his legacy mostly rested on AOL and his charity work. In the late 1990s, he joined with Fred Malek, a business executive with strong Republican ties, in funding a group to bring baseball to Washington. Major League Baseball ultimately chose the family of Theodore N. Lerner as owners of the Nationals.

His marriage to Bronwen Krummeck ended in divorce. Survivors include three sons, Mark Kimsey of McLean, Michael Kimsey of Prague and Raymond Kimsey of Washington; a sister, Eleanor O’Sullivan of Rockville, Md.; a brother, Thomas Kimsey of Charlottesville; and grandchildren.

Mr. Kimsey later reached an accommodation with Gonzaga. He received an honorary diploma. And Gonzaga got its own Kimsey Technology Center.