Chief of Clark Enterprises builds the stadiums sports fans cheer in: Camden Yards and M&T Bank Stadium (Baltimore); FedEx Field, Verizon Center and Nationals Park (Washington, D.C.); Miller Park (Milwaukee); Petco Park (San Diego). Company also builds museums, theaters, airport terminals, jails. Sales: $4 billion. Real estate arm owns millions of square feet of office space in Washington, D.C. area, plus 15,000 residential units. U. of Maryland home to A. James Clark School of Engineering. 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. 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. 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. Mr. Clark became company president in 1969. 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. 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. 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.