Bradley was born in Clark, Missouri the son of a schoolteacher. He was educated at local schools and intended to enter the University of Missouri. Instead he was advised to try for West Point. He placed first in his district exams for a place and entered the academy in 1911. Graduating from West Point in 1915 he was part of a class that contained many future generals. He joined the 14th Infantry Regiment but did not see action in Europe — serving on the Mexican border in 1915 and when war was declared he was promoted to captain but was posted to Montana. He did not receive a frontline command, his joining of the 19th Infantry Division in August 1918 was intended to lead to Europe but the influenza pandemic and then the armistice prevented him leaving the US.
Between the wars he taught and studied. From 1920-24 he taught mathematics at West Point. He was promoted to a major in 1924 and took the advanced infantry course at Fort Benning, Georgia. After a brief service in Hawaii he then studied at the Command and General Staff School at Fort Leavenworth in 1928-29. From 1929 he taught at West Point again, taking a break to study at the Army War College in 1934. He was promoted to lieutenant colonel in 1936 and worked at the War Department from 1938. In February 1941 he was promoted to brigadier general and sent to command Fort Benning. In February 1942 he took command of the 82nd Infantry Division before being switched to the 28th Infantry Division in June.
Bradley did not receive a frontline command until early 1943 after Operation Torch, he had been given VIII Corps but instead was sent to North Africa to serve under Dwight D. Eisenhower. He became head of II Corps in April and directed them in the final battles of April and May. He then led his corps onto Sicily in July. In the approach to Normandy Bradley was chosen to command the substantial 1st Army Group. During Operation Overlord he commanded three corps directed at the areas codenamed Utah and Omaha. Later in July he planned Operation Cobra which was the beginning of the breakout from the Normandy beach-head. By August Bradley's command, the renamed 12th Army Group, had swollen to over 900,000 men.
Bradley used his unprecedented force to undertake an ambitious plan to encircle the German forces in France, trapping them west of the Rhine. It was only partially successful but German forces were enormously attrited during their retreat. The American forces reached the 'Siegfried Line' in late September and were largely halted.
It was forces under Bradley's command who took the initial brunt of what would become the Battle of the Bulge. and it was forces under George Patton that would finally forced the Germanss back. Eisenhower and Bradley used the advantaged gained after the end of the battle to break the German defences and cross the Rhine into the industrial heartland of the Ruhr. The fortunate capture of the bridge at Remagen was quickly exploited, leading to an enormous pincer movement encircling the German forces in the Ruhr from the north and south, over 300,000 prisoners were taken. American forces met up with the Soviet forces near the River Elbe in mid-April. By this time the 12th Army Group was a force of four armies (1st, 3rd, 9th, and 15th) that numbered over 1.3 million men.
Bradley headed the Veterans Administration for two years after the war. He was made army chief of staff in 1948 and first official Chairman of the Joint Chiefs of Staff in 1949. On September 22, 1950 he was promoted to the rank of five-star general, only the fifth man to achieve that rank. Also in 1950 he was made the first Chairman of the NATO Committee. He remained on the committee until August 1953 when he retired from the military to take a number of positions in commercial life.
He published his memoirs in 1951 as A Soldier's Story and took the opportunity to attack the British wartime commander Bernard Montgomery over his 1945 claims to have won the Battle of the Bulge.
Since a five-star general is always part of the US Army, Bradley spent his last years at a special residence on the grounds of the William Beaumont Army Medical Center, part of the complex which supports Fort Bliss, Texas.
He is buried at Arlington Cemetery.