Born in South Philadelphia, Pennsylvania, he was a veteran Private First Class of Easy Company, 2nd Battalion, 506th Parachute Infantry Regiment (PIR) attached to the 101st Airborne Division of the United States Army during World War II. As a member of Easy Company, he fought in several major battles, including Operation Market Garden in Holland and the Battle of the Bulge in Bastogne, Belgium. He helped liberate the Kaufering concentration camp in Landsberg, Germany, and captured Hitler's Eagle's Nest (Kehlsteinhaus).123
Heffron wrote Brothers in Battle, Best of Friends: Two WWII Paratroopers from the Original Band of Brothers Tell Their Story with William "Wild Bill" Guarnere and Robyn Post, outlining the activities of Easy Company 1942-1945.
Heffron is portrayed in the Stephen Ambrose classic book Band of Brothers and played by Scottish actor Robin Laing in the Tom Hanks and Steven Spielberg produced HBO miniseries of the same name, and was one of the U.S. Army's first paratroopers.4