Barnum, 76, said he was one of only two recipients of the Medal of Honor -- the highest award for combat valor -- to be denied a ceremony at the White House amid widespread public disapproval of the Vietnam War.
"The administration at that time did not want any more publicity about the war," Barnum explained. "So I'm told that [then-Marine Corps Commandant] Gen. [Wallace] Greene said, 'He earned it, it's been approved, and if you won't decorate him, I will.' So I received the Medal of Honor in the [Sousa] Band Hall."
The DDG-124, to be built by General Dynamics Corp. at its Bath Iron Works facility in Maine, will be Barnum's namesake.
He received the Medal of Honor for heroism while on temporary assignment as a first lieutenant in Vietnam in 1965, an artillery forward observer with 2nd Battalion, 9th Marines. Trapped by an onslaught of accurate enemy fire on an isolated hill, Barnum was forced to take the lead after his company commander was grievously wounded and his radio operator was killed.
He took the radio and assumed command of the company under fire, mounting a successful counterattack and assisting with the evacuation of wounded and dead troops from the position.
"An O-2 on [temporary active duty] had, in a few hours, done more and showed more courage and selflessness than most of us do in a lifetime," said Navy Secretary Ray Mabus as he announced the naming of the destroyer.
Traditional naming conventions state that Arleigh Burke-class destroyers are supposed to be named for deceased members of the Navy, Marine Corps and Coast Guard. In his tenure as secretary of the Navy, Mabus has received attention for defying this tradition with regularity.
The USS Harvey C. Barnum Jr. will be the eighth ship Mabus has named for a living person, of less than two dozen total Navy ships named for living individuals.
Mabus told Military.com on Thursday that he does not see himself as defying tradition by naming ships after living people, but noted that he does see value in the practice.
"I think it's ... important, when we can, to honor people who are still with us and thank them for what they did," Mabus said. "In a tangible way, they can be part of that spirit for that ship that will be there long after all of us are gone."
Mabus said Barnum served in the military during a difficult period in American history and continued to serve following his military career, as deputy assistant secretary of the Navy for Reserve Affairs, as principal director for Drug Enforcement Policy at the Office of the Secretary of Defense, and as president of the Congressional Medal of Honor society, among other posts.
"It's important for Americans today to recognize people like Barney Barnum and everything he represents," Mabus said.
Barnum said he hoped to visit his namesake ship while it was under construction and to ride aboard her after she entered service. He plans to make himself available to future crews of the Barnum to answer their questions and talk about his own experiences.
"So it's an opportunity to influence a warfighter, a warfighting ship, and it's got great capacity and capabilities," he said. "I'm just looking forward to the opportunity to mentor and show support."