Murphy received the Medal of Honor for valor that he demonstrated at age 19 for single-handedly holding off a company of German soldiers for an hour at the Colmar Pocket in France in January 1945, before leading a successful counterattack while wounded.

After the attack on Pearl Harbor in 1941, Murphy's older sister helped him to falsify documentation about his birthdate in order to meet the minimum age for enlisting in the military.

After his mother died of endocarditis and pneumonia[20] in 1941, he worked at a radio repair shop and at a combination general store, garage and gas station in Greenville.

[24] After the Japanese attack on Pearl Harbor in December 1941, he attempted to enlist in the U.S. military,[21] but the Army, Navy, and Marine Corps all turned him down for being underweight and underage.

[42] Sidelined with illness for a week when Company B arrived in Palermo on 20 July,[43] he rejoined them when they were assigned to a hillside location protecting a machine-gun emplacement, while the rest of the 3rd Infantry Division fought at San Fratello en route to the Allied capture of the transit port of Messina.

[54] Taking shelter from the weather in an abandoned farmhouse on 2 March, Murphy and his platoon killed the crew of a passing German tank.

The Germans scored a direct hit on an M10 tank destroyer which was stationed near Murphy's company command post, setting it alight and forcing the crew to abandon it.

[82] Murphy mounted the abandoned, burning tank destroyer and began firing its .50 caliber machine gun at the advancing Germans, killing a squad crawling through a ditch towards him.

[84] The 3rd Infantry Division was awarded the Presidential Unit Citation for its actions at the Colmar Pocket, giving Murphy a Bronze Oak Leaf Cluster for the emblem.

[93][94] Near Salzburg, Austria, on 2 June 1945,[95] Lieutenant General A.M. Patch[23] presented Murphy with the Medal of Honor and Legion of Merit for his actions at Holtzwihr.

[ALM 4] Inquiries were made through official channels about the prospect of Murphy attending West Point upon his return to the United States, but he never enrolled.

[13][99] According to author Don Graham, Murphy suggested the idea and then dropped it, possibly when he realized the extent of academic preparation needed to pass the entrance exam.

[100] Murphy was one of several military personnel who received orders on 8 June 1945 to report to Fort Sam Houston in San Antonio, Texas, for temporary duty and reassignment.

[13][99] Upon arrival on 13 June, he was one of four assigned to Fort Sam Houston Army Ground & Services Redistribution Station and sent home for 30 days of recuperation, with permission to travel anywhere within the United States during that period.

He called on the government to give increased consideration and study to the emotional impact of combat experiences, and to extend health care benefits to war veterans.

After the 25 June 1950 commencement of the Korean War, Murphy began a second military career and was commissioned as a captain in the 36th Infantry Division of the Texas Army National Guard.

[ALM 6] When actor and producer James Cagney saw the 16 July 1945 issue of Life magazine depicting Murphy as the "most decorated soldier",[98] he brought him to Hollywood.

[136] The film's financial backers refused to bankroll the project unless Murphy was given the lead;[137] thus, Allied Artists put aside their reservations about using an inexperienced actor and gave him the starring role.

He wrapped up that year making Sierra starring Wanda Hendrix, who by that time had become his wife,[141] and Kansas Raiders as outlaw Jesse James.

Universal lent him to MGM in 1951 at a salary of $25,000[142] to play the lead of The Youth[ALM 7] in The Red Badge of Courage, directed by John Huston.

In 1953, he starred in Frederick de Cordova's Column South,[146] and played Jim Harvey in Nathan Juran's Tumbleweed, an adaptation of the Kenneth Perkins novel Three Were Renegades.

[150] Although Murphy was initially reluctant to appear as himself in To Hell and Back, the 1955 adaptation of his book directed by Jesse Hibbs, he eventually agreed;[151] it became the biggest hit in the history of Universal Studios at the time.

[152][153] To help publicize the release of the film, he made guest appearances on television shows such as What's My Line?,[ALM 8] Toast of the Town,[154] and Colgate Comedy Hour.

The partnership resulted in Murphy appearing as John Phillip Clum in the 1956 western Walk the Proud Land,[156] and the non-westerns Joe Butterfly[157] and World in My Corner.

[162] Murphy was featured in three westerns in 1959: he starred opposite Sandra Dee in The Wild and the Innocent,[163] collaborated as an uncredited co-producer with Walter Mirisch on the black and white Cast a Long Shadow, and performed as a hired killer in No Name on the Bullet, a film that was well received by critics.

[165] During the early 1960s, Murphy donated his time and otherwise lent his name and image for three episodes of The Big Picture television series produced by the United States Army.

[197] On 28 May 1971, Murphy was killed when the private plane in which he was a passenger crashed into the side of a mountain 14 nautical miles (16 mi; 26 km) northwest of Roanoke, Virginia,[198] in conditions of rain, clouds, fog, and zero visibility.

[200] The aircraft was a twin-engine Aero Commander 680 flown by a pilot who had a private-pilot license and a reported 8,000 hours of flying time, but who held no instrument rating.

[202] After her husband's death, Pamela Murphy moved into a small apartment and got a clerk position at the Sepulveda Veterans Administration Hospital in Los Angeles, where she remained employed for 35 years.

The latter was part of a speech Murphy had written at a 1968 dedication of the Alabama War Memorial in Montgomery, and later set to music by Scott Turner under the title "Dusty Old Helmet".