Buckles biographer David DeJonge, president of the WWI Memorial Foundation, said supporters have long hoped Congress would recognize the oversight and pass a law requiring a memorial on the mall.
"This is a very public and historic decision," he said, "and we feel that an overwhelming public poll would show that America would agree this memorial needs to be approved and on the mall."
Buckles was buried at Arlington National Cemetery after hundreds of people, including President Barack Obama and Vice President Joe Biden, paid their respects.
His grave is on the side of a hill ringed by cedar trees with views of the Washington Monument, Capitol dome and Jefferson Memorial to the north. At the crest of the hill sits the grave of Gen. John Pershing, under whose command Buckles served, along with a plaque commemorating the 116,516 Americans who died in World War I.
Buckles lied about his age to enlist at 16, then went on to outlive 4.7 million other Americans who served.
Born in Missouri and raised in Oklahoma, he never saw combat. He served as an ambulance driver in England and France, and after Armistice Day, he helped return prisoners of war back to Germany.
He returned to the United States in 1920 as a corporal. During World War II, Buckles was working as a civilian for a shipping company in the Philippines when he was captured as a prisoner of war. He spent more than three years in Japanese prison camps.
The last of the WWI veterans, Florence Green, died in February at 110. She served with the Women's Royal Air Force as a waitress at an air base in eastern England but wasn't officially recognized as a veteran until 2010.
The last known combatant, Royal Navy veteran Claude Choules, died in Australia months after Buckles. He, too, made it to 110.