Mr Biden delivered remarks and took part in a wreath-laying ceremony with vice-president Kamala Harris at the Tomb of the Unknown Soldier to mark Arlington’s 70th National Veterans Day Observance.
The president avoided any mention of the war in Gaza in his speech, as he comes under intense pressure to push for a ceasefire by Israeli forces.
As he spoke, pro-Palestinian protesters gathered near his Delaware home to call for an immediate end to the Israeli offensive which has claimed more than 11,000 lives in Gaza.
Mr Biden told how he could still feel the “overwhelming pride” as his son received the Bronze Star Medal posthumously for his service with the 261st Signal Brigade of the Delaware National Guard during his deployment to Iraq in 2008.
“Like so many of you, Veterans Day is personal to Jill and me,” he said.
“On this day I can still see my son, the attorney general of Delaware, standing ramrod straight as I pinned his bars on him the day he joined the Army National Guard in Delaware.”
Beau Biden, the president’s eldest son, died in 2015 from brain cancer that the president believes was linked to his exposure to toxic carcinogens from burn pits during his time serving in Iraq.
Mr Biden said he asked Beau why he had enlisted. “He said ‘Dad, it’s my duty’. That was the code my son lived by and the creed that millions of veterans have followed.”
The president touted new policies on veterans’ healthcare, which will see all living World War II veterans receive free medical treatment.
He announced he was expanding resources to the PACT Act, which helps veterans exposed to burn pits during active duty.
Mr Biden also announced the launch of a new Veteran Scam and Fraud Evasion task force.
He said the United States had “one truly sacred obligation” which was to care for soldiers after they returned from active duty.
“Only one per cent of our society today protects the other 99 per cent,” he said.