The British Army captain exchanged handshakes and stories with soldiers receiving physical therapy at the military rehabilitation center.
Prince Harry is "just one of the guys," one soldier wrote on Instagram.
He happily posed for pictures and swapped war stories with his fellow veterans.
Officials at Walter Reed showed the prince a high-tech treadmill that projects a virtual world on a screen and is used to help patients who have lost limbs with posture, balance and pain.
"We've got nothing like this back in the U.K." he said. "You guys as Americans are used to the technology; we are always behind."
He chatted with Staff Sgt. Tim Payne, 30, of Montana, who was injured by an IED in Afghanistan.
"We talked about how I got injured and that I like swimming," Payne said after. "I told him I swim 4,000 meters a day and someday will swim the English Channel. Harry said, 'That's a crazy idea.'"
"The recurring theme [of this trip] is to help recognise and bring a spotlight on to the work being done to help these outstanding young men and women."