Bob Slaughter was once described as perhaps the best-known D-Day veteran in America. National media outlets turned to him when they needed a first-person account of the Normandy invasion. At 6-foot-5, he was an imposing presence as he led President Bill Clinton across a windswept Omaha Beach during a 50th anniversary commemoration in 1994.

And by all accounts, the National D-Day Memorial in Bedford, Va., which was dedicated by President George W. Bush in 2001 and draws 75,000 visitors a year, would never have been built if not for Mr. Slaughter’s efforts.

Mr. Slaughter, 87, died May 29 at a hospital in Roanoke of complications from dementia, his son Bob Slaughter Jr. said. By the time of his death — and despite financial and legal problems that dogged the memorial after its opening — Mr. Slaughter was regarded as an unofficial memory keeper for the D-Day veterans.

He had assumed that role only after decades of silence about the events of June 6, 1944.

Mr. Slaughter joined the Virginia National Guard at 15, less than a year before the United States entered World War II. Alex Kershaw, a D-Day historian, wrote in an e-mail that Mr. Slaughter grew six inches between the time of his enlistment and the invasion. He had never expected to experience combat overseas.

Bob Slaughter was a veteran of the D-Day invasion. (Courtesy of National D-Day Memorial Foundation)

Yet there Mr. Slaughter found himself, a sergeant and squad commander in the largest amphibious assault in military history, forging his way through the bloody waters of the English Channel to the even bloodier Omaha Beach. Years later he described feeling like a “naked morsel on a giant sandy platter.”

As he surveyed the carnage, Mr. Slaughter recognized the faces of men he knew. Among the dead were soldiers who came to be known as the Bedford Boys — the infantrymen from Bedford, a small town in the Blue Ridge foothills that is said to have sustained greater losses per capita than any community in the United States on D-Day.

By the end of the Normandy campaign, 23 of the 35 Bedford Boys had died. Nineteen of them reportedly were killed during the first 15 minutes of the battle — less than an hour before Mr. Slaughter made his own landing.

When he came home in 1945, he found that, despite a hero’s welcome, few people understood the trauma he and other veterans had suffered. Mr. Slaughter got a job at the Roanoke newspaper, eventually becoming a composing room foreman. Occasionally he proposed news articles about the D-Day invasion, according to the Roanoke Times. He found no takers.

After his retirement from the newspaper in 1987 — nearly two decades before the National World War II Memorial opened on the Mall — Mr. Slaughter began imagining a monument for the Normandy veterans. Without such a tribute, he once said, the United States would have “no gathering place, no meeting hall, no memorial, where our country can collect its memories and the lessons we learned from D-Day.”

The project languished for several years but received a burst of momentum during the 50th anniversary D-Day commemorations, and Mr. Slaughter’s initially modest plans for the monument grew steadily more elaborate. He was “instrumental” in bringing the project to fruition, said Robin Reed, the president of the memorial’s foundation.

Mr. Slaughter became chairman of the foundation in 1994. He enlisted support from historian Stephen E. Ambrose and Steven Spielberg, the director of the 1998 D-Day film “Saving Private Ryan.” Peanuts creator Charles Schulz contributed $1 million. Bedford donated land for the memorial. Its centerpiece is a 44-foot arch inscribed with the word “Overlord,” the code name for the invasion.

A crowd of more than 20,000 gathered in Bedford — a town of a little more than 6,000 — for the memorial’s dedication on June 6, 2001. But four months later, Mr. Slaughter and nearly all the members of the board resigned when the foundation was revealed to be $5 million in debt because of construction cost overruns and other expenses.

Jeffrey R. Fulgham, the foundation’s vice president for finance and development, said the memorial has been debt-free for more than five years.

“They can’t take away from me what we already accomplished,” Mr. Slaughter told the Atlanta Journal-Constitution in 2002. “But, I wish sometimes I hadn’t gotten into it.”

John Robert Slaughter was born Feb. 3, 1925, in Bristol, Tenn. His father, a lumber worker, moved the family to Roanoke when Mr. Slaughter was a boy and died while his son was serving in Europe. After the war, Mr. Slaughter returned to Roanoke and married the former Margaret Leftwich in 1947.

Besides his wife, of Roanoke, survivors include two sons, John Robert “Bob” Slaughter Jr. of Warrenton and Hunter Slaughter of Roanoke; a sister; two grandchildren; and two great-grandchildren.

Mr. Slaughter chronicled his wartime experience in a 2007 memoir, “Omaha Beach and Beyond.” He received two bullet wounds in Normandy. His decorations included the Bronze Star Medal and several Purple Hearts.

“To say that I was fighting for democracy and idealism and the United States and apple pie and mother and all that then, no, that wasn’t what it was,” he said in a 1999 interview with CBS News. “It was fighting for each other, fighting for my buddies.”