Edwin C. Bearss, the former chief historian of the National Park Service and an authority on the Civil War who was instrumental in preserving battlefields and artifacts and developed a loyal following for his tours and dramatic recitations at Civil War sites, died Sept. 15 at an assisted-living facility in Richland, Miss. He was 97.

He had a recent heart attack, said his daughter, Jenny Bearss.

Mr. Bearss (rhymes with “farce”) developed a fascination with military history while growing up on a Montana ranch a few miles from the Little Bighorn Battlefield, where Lakota and Cheyenne warriors killed Gen. George Armstrong Custer and his soldiers in 1876.

He had a master’s degree in history, wrote dozens of books and pamphlets during his 40 years with the Park Service and was a memorable on-screen commentator in Ken Burns’s 1990 documentary series on the Civil War.

That year, Pulitzer Prize-winning historian James M. McPherson described Mr. Bearss as “a national historic treasure who probably knows more about the Civil War than any man alive.”

For Mr. Bearss, the life of an academic historian held little appeal. A week after joining the Park Service in 1955, in Vicksburg, Miss., he began to lead tours — and kept leading them, in one form or another, for the next 64 years.

“My classroom is thousands of acres,” he told the Washington Times in 1992. “I have thousands of students of all ages and expertise. I can’t see being confined to a single room.”

He preferred to stride a battlefield on foot, observing the slope of hills, the presence of trees, buildings, rivers and rocks. He visited the scene of every major battle of the Civil War and those of other wars, from the Revolutionary War and the War of 1812 to conflicts in the West between American Indians and White soldiers and settlers.

“The terrain,” Mr. Bearss told the Richmond Times-Dispatch in 2010, “pretty well dictates who’s going to win and who’s going to lose, who’s going to die and who’s going to live.”

On his tours, he walked quickly, carrying a military swagger stick in his hand. He spoke without notes, sometimes for hours on end, with the booming voice and dramatic flair of an actor. He often closed his eyes while talking, as if to peer more deeply into the past.

During Mr. Bearss’s frequent visits to the battlefield in Gettysburg, Pa., it wasn’t unusual for casual tourists to become enthralled until he was surrounded by a crowd of 500 or more. The flavor of his narrative style was captured by the Times-Dispatch in 2010, when Mr. Bearss was visiting Virginia’s Spotsylvania County and describing the scene after the Battle of the Wilderness in May 1864:

“So, as darkness closes in on the evening of the 7th down at the intersection of the Brock and Plank roads, where the ground fires are still burning from the previous day and you have the blackened corpses of soldiers . . . and the Union army comes to the crossroads and the men who have heretofore done the dying and the suffering know they are not turning back. They are going on. The Confederates will be correspondingly discouraged.”

In the 1950s and 1960s, he led efforts to raise the Union gunboat USS Cairo from Mississippi’s Yazoo River, where it sank in 1862. He was an early advocate for preserving historical battlefields and buildings in danger of destruction and redevelopment and was a member of the Civil War Sites Advisory Commission.

Mr. Bearss was transferred to Washington with the Park Service in 1966 and was its chief historian from 1981 to 1994. In addition to his Civil War tours and books — his three-volume study of the Vicksburg Campaign is scheduled to be republished soon — he helped establish presidential libraries and historical sites. He spoke to members of Congress about the importance of historical preservation.

Over the years, Mr. Bearss became something of a cult figure among professional and amateur historians of the Civil War. Many people, dubbed the “Bearss Brigade,” attended dozens of his tours, some of which lasted a week or longer.

Long after he retired from the Park Service in 1995, he continued to lead commercial tours for the Smithsonian Associates and other organizations and to speak at Civil War Round Tables, a nationwide network of meetings for people interested in the war’s history.

“You’ve got to be interesting,” Mr. Bearss told the Washington Times. “If you’re boring, they won’t get out. You have to make them want to hear what you’ve got to say. . . . You have to make them live it.”

Edwin Cole Bearss was born June 26, 1923, in Billings, Mont., and grew up on a ranch near Hardin, Mont. He rode a horse to school.

“I got interested in the Civil War in the seventh grade,” Mr. Bearss told Smithsonian magazine in 1995. “My father was a Marine in World War I. He liked to read aloud, war books. Then I got a biography of [Confederate Gen.] Jeb Stuart, and that was it.”

He gave cattle on the ranch names derived from Civil War generals and battles. After high school, he toured battlefields before enlisting in the Marine Corps in 1942.

On Jan. 2, 1944, Mr. Bearss was wounded by machine-gun fire during a battle at Cape Gloucester on the Pacific island of New Britain. He was struck in the left arm, right shoulder, buttocks and left heel, spent more than two years receiving treatment at military hospitals and never regained full use of his left hand.

“We romanticize war when we’re not actually fighting one,” he told The Washington Post in 1988.

During his convalescence, Mr. Bearss read widely about the Civil War and then used the G.I. Bill to study at Georgetown University, graduating in 1949 from its Foreign Service program. He spent three years as a civilian employee of the Navy.

While touring a historical site in Tennessee, Mr. Bearss was so impressed by his National Park Service guide that he asked how he could apply for a job. After receiving a master’s degree in history from Indiana University in 1955, he joined the Park Service as a historian.

He lived in Arlington, Va., for many years before moving to Mississippi shortly before his death.

His wife of 48 years, the former Margie Riddle, also a Civil War historian and preservationist, died in 2006. A daughter, Sara Beth Bearss, died in 2012. Survivors include two children, Edwin C. Bearss Jr. of Ellerslie, Ga., and Jenny Bearss of Brandon, Miss.; a brother; three grandsons; and four great-grandsons.

In later years, Mr. Bearss expanded his historical portfolio to Europe, leading groups on tours of battlefields from World War I and World War II, speaking with the same erudition and fire that he brought to his talks about the Civil War. He led his final tour, of historical sites near Richmond, in November.

“I think,” he told the Associated Press in 2003, “people want to walk on the ground that has been consecrated in blood.”