(CNN) -- "Faithful unto death."
Those words on the West Point headstone of 1st Lt. Alonzo H. Cushing succinctly enshrine the determination of the man who helped turn the tide at Gettysburg during the Civil War.
Despite two severe wounds, Cushing, 22, stayed at his post and directed artillery fire upon hordes of Confederate soldiers charging the center of the Union line at Cemetery Ridge -- a doomed assault known as Pickett's Charge. A bullet to the head finally felled the young officer.
More than 151 years after his stand, Cushing posthumously received the Medal of Honor in a White House ceremony on Thursday.
"As our country struggled for its survival, President Lincoln dedicated the battlefield at Gettysburg as a final resting place for those who died here that the nation might live," President Barack Obama said. "Today, the nation that lived pauses to pay tribute to one of those who died there."
The Medal of Honor is the country's highest military award, given to American soldiers who display conspicuous "gallantry above and beyond the call of duty."
The recognition for the West Point graduate marks the longest span of time between the event that merited the award and the bestowal of the medal, said the Congressional Medal of Honor Society.
Obama acknowledged Thursday that this recognition usually is given out within years of the event, "but sometimes even the most extraordinary stories can get lost in the passage of time."
"This Medal of Honor is a reminder that no matter how long it takes, it is never too late to do the right thing," the President said.
Helen Loring Ensign, 86, of Palm Desert, California, received the medal from Obama on behalf of Cushing's descendants, many of whom were in the White House Roosevelt Room for the ceremony.
Ensign is Cushing's first cousin, two generations removed, the closest surviving blood relative and primary next of kin, as confirmed by the U.S. Army. The soldier had no children.
Descendants told reporters before the ceremony that they plan to loan out the medal to West Point, where Cushing graduated; Gettysburg, Delafield, Wisconsin, where he was born; Fredonia, New York, where the young man grew up; and the McClurg Museum, in Westfield, New York.
John Heiser, historian at Gettysburg National Military Park, is among those who thinks the honor is well overdue.
"He does deserve it without a doubt," said Heiser earlier this year. "The tragedy is ... that it should have been awarded long, long ago."
Continued to fire, lead while wounded
The Civil War hero commanded the six-gun Battery A, 4th U.S. Artillery, at the momentous Pennsylvania battle.
Cushing's battery took a pounding from Confederate artillery preceding the attack and he had only two serviceable guns when the charge began on the hot afternoon of July 3, 1863. The estimated 13,000 attackers had what is known as "The Angle" as their objective, and some were able to briefly breach the stone wall.
Artillery shell fragments left Cushing with injuries to his shoulder and abdomen.
"Refusing to evacuate to the rear despite his severe wounds, he directed the operation of his lone field piece continuing to fire in the face of the enemy," the White House said in a statement when the decision to bestow the medal was announced. "With the rebels within 100 yards of his position, Cushing was shot and killed during this heroic stand. His actions made it possible for the Union Army to successfully repulse the Confederate assault."
Heiser said that the battery -- which included 126 officers and enlisted men -- had the misfortune of being in the center of the maelstrom on the third day of the pivotal battle.
"His battery was under fire for an hour and a half," Heiser said. "It was left in shambles and destroyed." Six men were killed and 32 were wounded.
Given the status of his wounds and his battery, Cushing had every reason to withdraw, said Heiser.
"He is going to show those Rebels one way or the other that his battery will be in action to the end," said Heiser. "It is upholding the highest level of what the Army says is honorable service."
Katie Lawhon, management assistant at Gettysburg, said visitors today can see where Cushing's battery served.
"The story of his valor and sacrifice at the center of the Union battle line ... is a very inspiring story to a lot of people who study Gettysburg," said Lawhon.
The lieutenant and his brothers all served in the Civil War. One sibling, Lt. William B. Cushing, is best known for sinking a Confederate ironclad during an October 1864 raid.
Honor for Cushing is a long time coming
Thursday's presentation culminates years of lobbying for the honor. Cushing was recommended in 2010, but Congress did not give formal approval until late last year.
Cushing received a waiver of a requirement that the Medal of Honor must be recommended within two years of the event and presented within three years, according to Laura Jowdy, archivist with the Congressional Medal of Honor Society.
The recommendation then had to go through the Defense Department and to the White House, where Obama gave his approval.
Margaret E. Zerwekh, 94, of Delafield, has been an integral part of the campaign, writing to Wisconsin congressmen and assisting with paperwork for Cushing's nomination. She's conducted research, and lives in a house on property formerly owned by the Cushing family.
"He saved the Union and he needs to have recognition for it," Zerwekh said this summer. "It is about time."
Obama acknowledged Zerwekh, who attended the ceremony.
"She managed to bring Republicans and Democrats together to make this happen. Margaret, we may call on you again," he said to laughs.
Heiser said the heroism of Cushing was "kind of forgotten, shoved to the background." A first sergeant in the battery years later received the Medal of Honor, while several surviving comrades kept alive Cushing's bravery.
The President paid tribute to others who fought and sacrificed all at Gettysburg.
"I might not be standing here today as president if not for the courageous sacrifices of these men," he said.
CNN's Greg Botelho contributed to this report.