President Trump marked the 75th anniversary of the D-Day invasion in Normandy at a ceremony at the grave site of more than 9,380 American service members who were killed in the World War II landings and the operations that followed.

“To the men that sit behind me and to the boys that rest in the field before me, your example will never grow old,” Mr. Trump said, with an audience of veterans behind him. “Your legend will never die.”

Mr. Trump and the first lady emerged from the president’s military helicopter just before 11 a.m., their arrival shown on two screens flanking the large stage. Cheers erupted from the audience for Mr. Trump, with some audience members taking off their caps and waving them.

President Emmanuel Macron of France and Mr. Trump greeted the more than 60 aging World War II veterans in attendance as they arrived onstage. Many were bundled with blankets, and at least one American veteran called out to Mr. Trump: “Hey, you’re our president, too. Come on up this way.”

At the ceremony, Mr. Trump shared stories of some of the veterans and families onstage by name and told of their connections to D-Day, as the crowd rose in applause for each of those honored.

The president paused several times, turned to the soldiers and family members onstage, and walked over and shook their hands. In one especially moving moment, Mr. Macron helped one of the men, 94-year-old Russell Pickett, rise to his feet as he momentarily struggled to stand.

Mr. Trump also remembered the lives lost in the operation, and though he has usually been critical of NATO during his time in office, he nodded to the military partnerships between the Allied nations.