A. James Clark was the founder and owner of Clark Construction, a Washington real estate establishment. (Michel du Cille/The Washington Post)

A. James Clark, the publicity-averse billionaire who owned one of the country’s largest general contracting conglomerates and whose construction projects — including Washington sports landmarks FedEx Field, Nationals Park and Verizon Center — affected the work and leisure life of hundreds of millions of people, died March 20 at his home in Easton, Md. He was 87.

The cause was congestive heart failure, said Robert J. Flanagan, executive vice president of Clark Enterprises.

Mr. Clark, who was chief executive of a sprawling construction, real estate and venture capital empire, grew up earning 10 cents an hour for summertime work on his grandmother’s Virginia farm.

His family could not afford to send him to an Ivy League architecture school, as he had hoped, so he spent years toiling as a civil engineer before moving into the executive suite. Over half a century, he built one of the largest fortunes in the United States.

The construction, renovation and expansion jobs he undertook are almost too numerous to count. Mr. Clark, whose surname is emblazoned on construction cranes from New York to California, built prisons, power plants, hotels, military barracks, government research facilities, museums, sports arenas and transportation projects, including 17 stations in the Washington-area Metro system. Forbes magazine once dubbed him the “King of Concrete.”

Mr. Clark also built a wall of privacy around himself and rarely consented to interviews about his life, career or philanthropy. He gave tens of millions of dollars to the University of Maryland, which named its engineering school after him, and to Johns Hopkins University.

He commuted most mornings by helicopter from his 750-acre farm on Maryland’s Eastern Shore to the Bethesda-based corporate headquarters of Clark Enterprises. He won his peers’ admiration by transforming Hyman Construction, the once-modest Washington company where he got his start in 1950, into a national juggernaut. (Hyman later became a subsidiary of Clark Enterprises.)

Among the projects Clark Enterprises oversaw in the Washington region were the Smithsonian Institution’s National Museum of the American Indian, the Women in Military Service for America Memorial near Arlington National Cemetery, the Walter E. Washington Convention Center, the U.S. Institute of Peace headquarters, the AARP headquarters, the Canadian Chancery near the National Gallery of Art and the new $435 million U.S. Coast Guard headquarters on the site of the old St. Elizabeths Hospital in Southeast Washington.

Clark Enterprises’s ventures elsewhere included stadiums such as Baltimore’s Oriole Park at Camden Yards, Milwaukee’s Miller Park and San Diego’s Petco Park; convention and trade centers in Miami, Boston and Nashville; and the Ronald Reagan State Office Building in Los Angeles, to name a few.

Mr. Clark’s conglomerate handled the restoration of the Willard hotel in the District and the Los Angeles County Hall of Justice. His businesses also built an addition to the Lincoln Center for the Performing Arts in New York and an expansion of the McCormick Place convention center in Chicago, among scores of other high-profile, city-center projects.

A numbers man

As a young man, Mr. Clark had become known as one of the savviest “number men” in the business. He often could correctly estimate the cost and profit potential of a proposed deal within minutes. His reputation and closely managed relationships with premier developers allowed him to obtain equity stakes as high as 20 percent in the properties. This compensation model helped Mr. Clark amass his considerable fortune.

“You don’t get in the Forbes 400 by just being a contractor,” said William A. Regardie, a former publisher of Regardie’s business magazine in Washington. “You get it by pieces of deals.” (In March, Forbes listed Mr. Clark’s worth as $1.6 billion, making him the 309th-richest person in the United States.)

Alfred James Clark, the son of a life insurance salesman, was born Dec. 2, 1927, in Richmond and grew up in Bethesda. He was a 1945 graduate of the old Devitt Preparatory School in Washington.

After completing the University of Maryland’s engineering program in 1950, he became a field engineer at Hyman and took night courses in accounting at American University with the hope of rising in the firm’s hierarchy.

“I did not want to go out at 5:30 in the morning with my stocking cap and my navy pea coat on and shoot lines and grades for the rest of my life,” he told the business publication Warfield’s in 1989.

By the late 1950s, he had become an estimator and then second-in-command at Hyman. He pushed the company, founded in 1906, to think on a grander scale. He pushed back against the belief held by some Hyman executives that quality and cost could be controlled only in smaller-scale projects. Mr. Clark was convinced that the company, which had revenue of $3.5 million when he arrived, could join the front ranks of the fiercely competitive construction industry.

As a result of his influence, Hyman became involved in major Washington projects, such as the construction of L’Enfant Plaza and what would become known as the Dirksen Senate Office Building. When Mr. Clark became company president in 1969, Hyman’s annual revenue was reportedly $57 million. During the next decade, that number grew tenfold as Mr. Clark aggressively opened offices from Georgia to California amid a construction boom in the Sun Belt.

Later, as the private development market slowed in the late 1980s and early 1990s, Mr. Clark focused on projects sponsored by federal and state governments and that provided a steadier source of income.

Meanwhile, Hyman became one of the biggest construction firms in the Washington area. Often working with Oliver T. Carr, one of the city’s most prominent developers, Mr. Clark helped build or add to hundreds of office projects in downtown Washington — and took an equity stake in many of them.

Taking on the unions

Hyman was a union shop. In 1977, Mr. Clark started Omni Construction as an open contractor in an effort to position the firm to compete more effectively against other companies with lower wage costs. It was a gamble. Few businesses in the Washington area had openly started nonunionized sister companies — a practice known as “double-breasting” — for fear of irritating trade unions.

“If I didn’t provide the service, someone else would,” Mr. Clark told the Engineering News Record in 1982.

Omni won the bid for Georgetown’s luxury Four Seasons Hotel, among other lucrative assignments. During its first few years, it won dozens of projects worth hundreds of millions of dollars.

In 1982, Omni and Hyman were named subsidiaries of the new Clark Construction Group, which became the centerpiece of the Clark Enterprises conglomerate. Other subsidiaries over the years included a coastal and air freight shipper called Clark Transportation, the real estate development concern Seawright Corp., and a commercial radio firm known as Clark Broadcasting.

In 1995, Omni and Clark Construction combined to become the third-largest general contractor in the United States. They began operating as Clark Construction, a nonunion business.

In 1950, Mr. Clark married Alice Bratton. Besides his wife, survivors include three children, Paul Clark of Mill River, Mass., and A. James Clark Jr. and Courtney Clark Pastrick, both of Bethesda; and 10 grandchildren.

Mr. Clark had an apartment at the Watergate complex and a home in Vero Beach, Fla., but he was said to prefer his remote farm in Easton.

“I’ve always kept a low profile,” he told Warfield’s, “and I like it that way.”