War in Afghanistan Medal of Honor Recipient. He received the award posthumously (presented to his widow) from President Donald Trump at the White House on August 22, 2018, for his actions as an Air Force Special Tactics Combat Controller technical Sergeant attached to a U.S. Navy Sea, Air, and Land (SEAL) team on March 4, 2002, near Takur Ghar, Afghanistan. He enlisted in the U.S. Air Force in September 1985, and was trained as an Information Systems Operator. He then cross-trained into the Combat Control career field and served with the 1721st Combat Control Squadron at Pope Air Force Base, North Carolina, from August 1990 to November 1992. On March 4, 2002, he and members of the U.S. Navy SEALs saw combat action in Operation Anaconda as a part of Operation Enduring Freedom in Afghanistan, and on that day, as he was attempting to rescue a fellow SEAL, he was killed. He was credited with saving the lives of the entire rescue team. Originally awarded an Air Force cross for his courage and valor in combat, upon further review by U.S. Air Force Secretary Deborah Lee James, it was upgraded to a Medal of Honor. He was also awarded the Purple Heart. His Medal of honor citation reads: "Technical Sergeant John A. Chapman distinguished himself by extraordinary heroism as an Air Force Special Tactics Combat Controller, attached to a Navy Sea, Air, and Land (SEAL) Team conducting reconnaissance operations in Takur Ghar, Afghanistan, on March 4, 2002. During insertion, the team's helicopter was ambushed, causing a teammate to fall into an entrenched group of enemy combatants below. Sergeant Chapman and the team voluntarily reinserted onto the snow-capped mountain, into the heart of a known enemy stronghold to rescue one of their own. Without regard for his own safety, Sergeant Chapman immediately engaged, moving in the direction of the closest enemy position despite coming under heavy fire from multiple directions. He fearlessly charged an enemy bunker, up a steep incline in thigh-deep snow and into hostile fire, directly engaging the enemy. Upon reaching the bunker, Sergeant Chapman assaulted and cleared the position, killing all enemy occupants. With complete disregard for his own life, Sergeant Chapman deliberately moved from cover only 12 meters from the enemy, and exposed himself once again to attack a second bunker, from which an emplaced machine gun was firing on his team. During this assault, from an exposed position directly in the line of intense fire, Sergeant Chapman was struck and injured by enemy fire. Despite severe, mortal wounds, he continued to fight relentlessly, sustaining a violent engagement with multiple enemy personnel before making the ultimate sacrifice. By his heroic actions and extraordinary valor, sacrificing his life for the lives of his teammates, Technical Sergeant Chapman upheld the highest traditions of military service and reflected great credit upon himself and the United States Air Force."

In August 2018, sixteen years after his death, Tech Sergeant (TSgt) Chapman received the Medal of Honor. The following day, TSgt Chapman was promoted to the rank of Master Sergeant (MSgt). His military marker does not yet reflect the new rank or his Medal of Honor.