Charles Payne was thrust into the media spotlight when Barack Obama told a veterans' group in May 2008 that Mr Payne - his great-uncle - had been present as a US soldier at the liberation of Auschwitz, the Nazi death camp.
Mr Payne says he has "no heroic story to tell"
The remark - which Mr Obama made while on the campaign trail - was seized upon by Mr Obama's critics, after it was pointed out that Auschwitz was liberated by Soviet troops.
But he was one of the first US soldiers to enter Ohrdruf, a sub-camp of the notorious Buchenwald complex.
Because of this family connection, Mr Obama chose to visit Buchenwald during his June 2009 visit to Europe.
And Mr Payne is set to accompany his great-nephew during a ceremony in Normandy to mark the 65th anniversary of the D-Day landings.
'Skin and bones'
Born in 1925, Mr Payne, the younger brother of Mr Obama's grandmother, Madelyn Dunham, was a private in the US Army's 89th Infantry Division during World War II.
Served as a private in the 89th Infantry Division during WWII
Became Assistant Director of the University of Chicago Library after the war
He landed in Normandy in January 1945, some months after the D-Day invasion.
By the time he arrived in Ohrdruf, German troops had long deserted the place.
"I remember the whole area before you got to the camp, the town and around the camp, was full of people who had been inmates," he recently told the Associated Press.
"The people were in terrible shape, dressed in rags, most of them emaciated, the effects of starvation. Practically skin and bones."
He recalls speaking to a freed prisoner about what had happened at the camp:
"With great difficulty we conversed and, if I got what it was he was telling me about, it was that the Germans had killed a million Jews and that the world didn't really know this yet."
But he is keen to minimise his role in the liberation.
"I have no heroic story to tell," he said. "I was just there."
"Until Barack misspoke about the name of the concentration camp and brought me to the attention of the media, I hadn't really thought about the war for a long time," Mr Payne added.
After the war, Mr Payne went to college in Kansas, and then on to graduate school at the University of Chicago.
He later specialised in the use of computers in libraries, retiring at the age of 70 as the assistant director of the University of Chicago Library.
A proud supporter of his great-nephew's presidential campaign, he has described Mr Obama as "truly an astounding young man".