Some five decades after he led a platoon credited with rescuing dozens of soldiers pinned down by enemy fire, a Vietnam War veteran will be awarded the nation's highest military honor for valor, the White House announced on Tuesday.

In May 1967, Army Maj. Charles Kettles led several helicopter trips to help evacuate wounded soldiers near the district of Duc Pho. He returned to the landing zone without additional aerial support to rescue stranded soldiers pinned down by enemy fire. The White House says Kettles helped save the lives of 40 soldiers.

Kettles retired from the Army in 1978 as a lieutenant colonel. He resides in Ypsilanti, Michigan, with his wife, Ann.

The Army said next month's White House ceremony is the culmination of an effort that began in 2012.

William Vollano of the Veterans History Project launched a formal campaign to upgrade Kettles' Distinguished Service Cross to the Medal of Honor.

As part of that review, several men from his company and the 101st Airborne Division sent letters validating Kettles' actions. Lawmakers also got involved. Longtime Democratic Rep. John Dingell of Michigan sent a letter to the Pentagon asking for reconsideration so that Kettles could be awarded the Medal of Honor.

Then, after Defense Secretary Ashton Carter determined that Kettles' actions merited the nation's highest military honor, Rep. Debbie Dingell and Sens. Gary Peters and Debbie Stabenow, all of Michigan, introduced legislation waiving a time limitation for the award and paving the way for Obama to make the final decision.

The Army also announced that Kettles will be inducted into the Pentagon's Hall of Heroes on July 19, one day after the White House ceremony.

The Army said that despite a heavily damaged helicopter, Kettles was relentless in his efforts to ensure that every soldier was extracted.

On one particular flight out of the landing zone, a machine gun sprayed the helicopter Kettles was flying, but "Maj. Kettles coaxed the helicopter and managed to fly us back to base camp," said Roland J. Scheck, an Army specialist who was serving as a door-gunner on Kettles' crew.

"Kettles personifies the Army's `Warrior Ethos' - never leave any soldier behind," said Secretary of the Army Eric K. Fanning.