Lieutenant General John Wilson O'Daniel (February 15, 1894 – March 27, 1975), nicknamed "Iron Mike", was a senior United States Army officer who served in World War I, World War II, and the Korean War. He is perhaps best known for serving with the 3rd Infantry Division in North Africa, Sicily, Italy, and Southern France during World War II. He was the commanding general (CG) of Audie Murphy, the most decorated soldier in the U.S. Army during World War II.

O'Daniel was an athlete, a teacher, a diplomat, and a lifetime military professional. He was short of stature (five foot six inches), an outspoken, doughty, gravel-voiced, combat leader of men through three major wars (World War I, World War II and the Korean War) spanning a forty-year military career. His motto was, "sharpen your bayonet". In his memoirs, General Dwight D. Eisenhower called him "one of our outstanding combat soldiers". The press likened him to General George S. Patton Jr. for his strong personal opinions and his fearless demeanor, as well as his dash and daring in moving the 3rd Infantry Division across the European Theater of Operations (ETO).

Early life John Wilson O'Daniel was born in Newark, Delaware on February 15, 1894. He graduated from high school at Oxford, Pennsylvania in 1912 and attended Delaware College in Newark, Delaware (now known as the University of Delaware), where he played varsity football and received the nickname "Mike". He enlisted in the Delaware National Guard in 1913 with Company E, 1st Delaware Infantry. On July 19, 1916, he was mobilized, and served as a corporal and sergeant with the First Infantry at the Mexico border in Deming, New Mexico. He was honorably discharged from service on his 23rd birthday, February 15, 1917.

Early military career and World War I After graduation from Delaware College in 1917, the same year the United States entered World War I, he was commissioned as a second lieutenant into the Infantry Branch of the United States Army Reserve on August 15 at Reserve Officers Training Camp at Fort Myer, Virginia. He received his regular commission on October 26 and was assigned to the 11th Infantry Regiment, part of the 5th Division, at Camp Forrest, Tennessee. O'Daniel was assigned to command a platoon in K Company of the regiment. His company commander, First Lieutenant Mark W. Clark, would go on to become a great friend and would be destined to play a large part in the newly commissioned O'Daniel's future military career.

In May 1918 he was, together with the rest of his battalion and division, shipped out to the Western Front to reinforce the American Expeditionary Forces (AEF), commanded by General John J. Pershing, for the remainder of the war and many months afterward. He took over command of the K Company when Clark, now a captain, was promoted to command the battalion, only to be wounded soon after. O'Daniel participated in the Battle of Saint-Mihiel, where he was badly wounded on September 12, 1918, the first day of the battle. Testifying to his endurance and aggressiveness in battle was his nickname, "Iron Mike", awarded by his peers, said to be a result of his actions at Saint-Mihiel, where he fought for twelve hours, even though he was hit in the face by a German machine gun bullet and severely wounded. It was for this action that he was later awarded the Distinguished Service Cross (DSC), the nation's second highest award for valor, for his actions, as well as the Purple Heart. The citation for his DSC reads:

He recovered shortly afterward and went on to participate in what was, and still is, the largest battle in the history of the U.S. Armed Forces, the Meuse–Argonne offensive.

After the war ended, on November 11, 1918 at 11:00am, he returned with the regiment to the United States in September 1919 and was later transferred to the 25th Infantry Regiment at Camp Stephen D. Little at Nogales, Arizona.

Between the wars O'Daniel became an infantry instructor with New Jersey National Guard at Trenton in May 1924. In September 1927 he entered the Infantry School at Fort Benning Georgia and graduated in May 1928. He was transferred in July 1928 to the 21st Infantry at Schofield Barracks, Hawaii and in January 1930 was placed in command of the Military Police Detachment of the Hawaiian Department at Fort Schafter. In October 1931 he joined the 12th Infantry at Fort Howard, Maryland.

In the 1930s with the country locked in the Great Depression, O'Daniel undertook a series of assignments that departed from traditional military roles. In May 1933, O'Daniel became assistant to the Officer in Charge of the New York Port of Embarkation for the Pilgrimage of War Mothers and Widows. From September to November 1933, he was on Civilian Conservation Corps duty at Smokemont, North Carolina and then was assigned to the 22nd Infantry Regiment at Fort Oglethorpe, Georgia. In July 1934 he was appointed Army liaison officer with the Tennessee Valley Authority. In March 1935 he became adjutant of District "D" of the Civilian Conservation Corps at Fort McClellan, Alabama. He was named Executive Officer of District "D" in July 1935, earning advancement to major in August, and a year later he became Professor of Military Science and Tactics at the Academy of Richmond County at Augusta, Georgia.

O'Daniel entered the Command and General Staff School at Fort Leavenworth, Kansas, in September and graduated in June 1939. He was then assigned to Fort Brady, Michigan as an instructor of the Citizen's Military Training Camp and Officer's Reserve Corps. In August 1939 he became branch instructor in the Michigan Military Area with headquarters in Detroit. On August 18, 1940, O'Daniel was promoted to the rank of lieutenant colonel.

World War II In January 1941, during World War II (although the United States was still neutral), he became commander of the 2nd Battalion, 24th Infantry Regiment at Fort Benning with which he participated in the Third Army maneuvers in Louisiana–a critical test of logistical and combat capabilities for the later fighting in World War II. O'Daniel's regimental commander, Colonel Charles Lockett, "wrote that Iron Mike was the best battalion commander he had ever seen".

Shortly after the American entry into the war, on December 24, 1941, he was promoted to colonel and became Assistant Chief of Staff for operations of the Third Army and Director of the Junior Officers Training Center in San Antonio, Texas. In June 1942 he was named Operations Officer of the Amphibious Training Center at Camp Edwards, Massachusetts.

North Africa, Sicily and Italy In July 1942 O'Daniel was transferred to Allied Forces Headquarters (AFHQ) in Europe as Commander of the American Invasion Training School in the United Kingdom. In September he assumed command of the 168th Infantry Regiment, part of the 34th Infantry Division, a National Guard formation under Major General Charles W. Ryder, leading it in the Allied invasion of French North Africa (Operation Torch), and led the regiment on November 8–9, 1942 in the capture of Algiers and the subsequent run for Tunis. He was also rewarded with a promotion to the one-star general officer rank of brigadier general, on November 20. In December, he was assigned by Lieutenant General Mark W. Clark (who had served with O'Daniel in the 11th Infantry in World War I) to organize the U.S. Fifth Army Invasion Training Center in North Africa which trained the forces for future amphibious landings.

In July 1943 O'Daniel landed in Sicily (which was given the codename of Operation Husky) with the 3rd Infantry Division, under Major General Lucian Truscott. On July 24, 1943, two weeks after the initial landings on Sicily, he returned to Algiers and was attached to the inexperienced 36th "Texas" Infantry Division, another National Guard formation, recruiting from Texas, under the command of Major General Fred L. Walker, for the Salerno landings (Operation Avalanche) in September. Although not required to do so, he chose to land with the troops at Salerno, landing with the 36th's 142nd Infantry Regiment, and, in the words of his biographer, Timothy R. Stoy, "played a significant role in defending the beachhead, as well as the conduct of beach operations for the 36th Infantry Division". His performance during the fighting continued to impress his more senior commanders, in particular with Walker, who had served with "Mike" in the 1920s, and who later personally awarded O'Daniel with the Silver Star.

Again, his stay was short as he became officer in charge of amphibious operations for the Fifth Army on October 10, and the following month he succeeded Brigadier General William W. Eagles as the assistant division commander (ADC) of the 3rd Infantry Division, still commanded by Major General Truscott, which had landed in Italy the month before. The division crossed the Volturno Line and advanced up the spine of Italy until being held up by the formidable German Winter Line (also known as the Gustav Line) defenses. The division, after spearheading the Fifth Army's advance and having seen much hard fighting and sustaining heavy casualties, was withdrawn for rest in November.

He took part in the landings at Anzio (Operation Shingle) in January 1944. Operation Shingle was an amphibious assault around the Italian town of Anzio in an attempt to outflank the Gustav Line and capture the Italian capital of Rome. In February O'Daniel assumed command of the 3rd Infantry Division from Major General Truscott, who was promoted to the command of VI Corps from Major General John P. Lucas, while still on the Anzio beachhead. While under his command the division repelled several furious German counterattacks, finally breaking out of the beachhead encirclement in May during Operation Diadem and driving to Rome, where he was promoted to the two-star rank of major general. He was also awarded the Army Distinguished Service Medal for his service in Italy and, on May 30, 1944, he was promoted to major general.

Much publicized, if not completely reported, was the comment he made at a staff meeting in response to a question from British General Sir Harold R. L. G. Alexander, Commander-in-Chief (C-in-C) of the Allied Armies in Italy (later redesignated the 15th Army Group). "I believe your division did not give an inch", asked General Alexander. "Is that true?" The reply from O'Daniel was "Not a God-damned inch."

Western Europe

He served there until August 1944 when O'Daniel and his 3rd Division landed at the St. Tropez Peninsula in Southern France and drove north through the Vosges Mountains to Germany. O'Daniel led the 3rd Division up the Rhône Valley to Strasbourg, in the Colmar Pocket where it decimated German forces in January 1945 and when it smashed across the Siegfried Line at Zweibrücken in March 1945. He frequently flew over the front lines in a light airplane dropping notes to the troops below, exhorting them to advance. He led the division across the River Rhine and participated in the capture of the Nazi citadel at Nuremberg on April 20, 1945, after ruthless house to house fighting. O'Daniel hoisted his flag over Adolf Hitler Square in the center of the city and paid a rousing tribute to the exhausted infantrymen around him for having "driven the hun" from one of the last remaining Nazi strongholds.

Just before noon on April 20, 1945–Adolf Hitler's birthday–the 2nd Battalion of the 30th Infantry Regiment reached the Adolf Hitler Platz in the center of the town after taking its ground in a building-to-building fight. The street markers in the square were replaced by others bearing the name "Eiserner Michael Platz" (Iron Mike Square) in honor of the 3rd Division's CG, Major General John W. O'Daniel, who was known to his intimate friends and to thousands of Marnemen as "Iron Mike."