Dewberry, a privately held professional services firm, with a proven track record of client service to public- and private-sector clients within the built and natural environments, has appointed David J. Mahoney, PE, chief executive officer, effective April 1, 2026. Mahoney has also been appointed to Dewberry’s board of directors. A driving force behind growing the firm’s portfolio of large, complex projects and managing risk, Mahoney will be based in Fairfax, Virginia, Dewberry’s national headquarters. He succeeds Donald E. Stone, Jr., who will serve in an advisory role through June 30 after which he plans to retire.
Commenting on the appointment, Executive Chairman Barry K. Dewberry says, “Dave has the right experience and energy to lead this company, now in its 70th year in business, and into the future. Our growth trajectory continues to be strong, and he has the strength of leadership and respect of our peers to deliver what the clients and communities we serve expect: strong relationships and excellent results.”
Mahoney has transformed Dewberry’s alternative project delivery practice, delivering a portfolio of more than 175 design-build projects and a construction value of over $23 billion, particularly for transportation agencies, water utilities, and other key clients. He was promoted to president of Dewberry’s holding company in 2025. In this role, he has led the firm’s alternative project delivery operation and associated risk management programs, through which he has been closely involved with all of Dewberry’s business lines and internal support services. He has taken the lead on many of the firm’s largest alternative delivery projects, determining the risk profile, project approach, teaming decisions, and negotiation. Through his leadership, Dewberry has also established trusted relationships and strategic partnerships with construction companies within its major market sectors.
Mahoney has also led Dewberry’s transportation practice since 2017, overseeing more than $25 billion in construction and generating more than $1.5 billion in revenue for the firm, for premier transportation agencies across the nation, such as departments of transportation in Virginia, New York, New Jersey, Pennsylvania, Maryland, North Carolina, Florida, and California; as well as the New Jersey Turnpike Authority, Metropolitan Transportation Authority, Central Florida Expressway Authority, and the Washington Metropolitan Area Transit Authority. He has served as a project manager on projects ranging from $50 million to $500 million in construction value, taking special interest in mentoring and developing staff who now lead major design-build projects and public-private partnerships, valued in the billions.
Mahoney has more than four decades of experience and joined Dewberry in 1986. Rising from a project engineer to ultimately managing complex and high-profile projects that have shaped the Greater Washington, D.C., region, his experience includes the Dulles Corridor Metrorail project, multiple phases of the Intercounty Connector (MD Route 200), multiple phases of the Fairfax County Parkway, and the extensive Route 28 corridor improvements in Northern Virginia.
Mahoney earned a bachelor’s degree in civil engineering from South Dakota State University (1984).