Groves received the most important assignment of his career in 1942 when, after receiving the rank of temporary brigadier general, he was appointed commanding officer of the highly secret Manhattan Engineer District, better known as the Manhattan Project, with a $2-billion budget and broad powers to tap the country's resources to develop, construct, and test the atomic bomb. He also established an air force unit to drop the bomb and a committee to recommend sites for its delivery. Promoted to permanent brigadier general and awarded the Distinguished Service Medal in 1945, Groves retired from the army in 1948. Subsequently, he was vice president in charge of research at the Remington Rand Corp. until his retirement in 1961.
See his Now It Can Be Told: The Story of the Manhattan Project (1962); biographies by W. Lawren (1988) and R. S. Norris (2002).
Descended from French Huguenots who came to America in the 17th century, Leslie Groves was the son of a U.S. Army chaplain. He was born in Albany, New York, and educated at the University of Washington and MIT before attending West Point. Groves graduated in 1918, fourth in his class, and was commissioned into the Army Corps of Engineers, completing his engineering studies at Camp A. A. Humphreys (now Fort Belvoir), 1918–21. He married Grace Hulbert Wilson in 1922.
Groves worked in various assignments throughout the United States and served with distinction in Nicaragua. In October 1934, he was attached to the Office of the Chief of Engineers and received a promotion to captain. Following courses at the General Staff College at Fort Leavenworth (1936) and the Army War College (1939), he was promoted to major in 1940 and posted to the General Staff in Washington. He was deputy to the Chief of Construction and oversaw a number of projects including the construction of the Pentagon in 1940. In the same year, he was promoted to colonel.
By this time, Groves had developed a reputation as an officer of high intelligence, tremendous drive and energy, and great organizational and administrative ability, as well as considerable ruthlessness, arrogance, and self-confidence. His success in overseeing a huge number of construction projects costing billions of dollars during the mobilization period between 1940 and 1942 made him a natural choice to take charge of the fledgling atomic bomb program.
Groves was important in most aspects of the bomb's development, including determining the sites to be used, finally deciding on Oak Ridge, Tennessee, Los Alamos, New Mexico, and Hanford Engineering in Washington state, as the primary sites for theoretical research and materials production. He made critical decisions on prioritizing the various methods of isotope separation, acquiring raw materials needed by the scientists and engineers, and in creating the army air force bomber unit which would deliver the finished bombs to their targets. He largly advocated the choice of Kyoto as lead target, citing its tremendous cultural importance; he reasoned that the city's highly educated population would better appreciate the significance of the new weapon, thereby increasing its political impact. His wish to destroy the city was overruled by Secretary of War Henry Stimson, who had honeymooned there. He was involved in collecting military intelligence on German atomic research and helped determine which cities in Japan were chosen as targets. Groves also blanketed the Manhattan Project with an unprecedented degree of security (which, however, failed to prevent the Soviets from conducting a successful espionage program that stole some of its most important secrets).
Though his conservative, rigid temperament and cold, blunt manner alienated some of the scientists he worked with, he also (against the advice of everyone he consulted) took the risky step of putting J. Robert Oppenheimer (a leftist intellectual and Groves' opposite in almost everything) in charge of Los Alamos, where the bomb was designed and assembled, trusting in the physicist's abilities. Groves' choice proved inspired, for Oppenheimer's brilliant, charismatic leadership was decisive in creating workable designs and getting them transformed into usable bombs.
Groves' greatest contribution to the Manhattan Project was in imparting his own driving energy and determination to get the bomb built as quickly as possible. He was the key leader in transforming what had been a slow paced, poorly coordinated, theoretical and laboratory research effort of a few universities into a fast moving, highly articulated, truly massive juggernaut involving thousands of scientists, engineers, technicians, workmen, and soldiers, as well as hundreds of companies and governmental organizations, spread all over the United States and the world.
As chief of the atom bomb program during the wartime emergency, Groves accrued an enormous amount of power. In the words of a subordinate, he "... planned the project, ran his own construction, his own science, his own Army, his own State Department and his own Treasury Department". Doing so, Groves ran roughshod over many people and made many enemies, some of them quite powerful. These enemies eventually succeeded in drastically reducing Groves' power and authority as control over atomic energy was transferred from military to civilian hands (from the Manhattan District to the Atomic Energy Commission) in January, 1947.
For a time, Groves continued to play a role at Los Alamos as head of the Armed Forces Special Weapons Project, but he eventually realized that in the rapidly shrinking post-war Army he would not be given any assignment approaching in importance the one he had held in the Manhattan Project (such posts would go to combat commanders returning from overseas). He decided to leave the Army. He was promoted to Lieutenant General just before his retirement on February 29, 1948 in recognition of his leadership of the bomb program.
Some activists believe, incorrectly, that Groves was one of the early proponents of using depleted uranium. A memo alleged to be on that subject, is often cited on the Internet. However, a close reading of the memo, which is actually a composite of several documents, including some pages not attributable to Groves, shows that the material under discussion was fission products and not uranium.
In 1955, a reporter asked Groves how the secret of the atomic bomb was "so well kept", (apparently forgetting that it wasn't well kept from the Soviets) who recorded this reaction: "If you have ever been the object of his direct look, you will know why I dropped my pencil in utter confusion when he said, 'Mainly by not talking to reporters.'" The reporter laughed, Groves laughed and the interview went on.
Groves' role in the Manhattan Project has attracted a continuing interest in film. He was the character played