Jean Marley O’Leary began working for General Leslie Groves in June 1941, when she was hired as his personal secretary.
The eldest of four, Eugenie (Jean) was raised in New York and attended Sacred Heart Academy. She was born on December 31, 1909. After graduating, Jean went to work for Time magazine in New York City. In 1929, she married William O’Leary, who worked for the Jersey Journal newspaper. They had one child, named Coni, who was born in 1931. After her husband’s death in March 1940, she applied to work for the federal government and was offered a position in the typing pool of the Office of the Quartermaster General.
In the spring of 1941 O’Leary’s secretarial skills caught Groves’ attention. Groves had a reputation for his brisk treatment of secretaries, and his first encounter with O’Leary was no exception. She responded to his stern, teasing sense of humor in kind and then refused to speak to him at all. She was not afraid of his rank, his position, or his treatment of others. While most men of his rank would have been offended, Groves respected people who stood up to him; normally, it showed a person with some courage and character.
In June 1941, Jean was assigned to Groves. Her secretarial and managerial skills soon made her invaluable, and the two worked together very well. When Groves assumed control of the Manhattan Project in September 1942, he and Mrs. O’Leary moved to two small offices on the fifth floor of the New War Department Building.
Those who had frequent contact with Groves throughout the Project began to refer to Jean as Major O’Leary. She was responsible for running the office and helped keep the General’s busy work schedule organized. She would remind him of important appointments and phone calls and composed letters on his behalf herself. If he was not around, sometimes she would sign them herself.
O’Leary was also the only secretary permitted to take notes on the deliberations of the Military Policy Committee, the Combined Development Trust, and other important groups that came to meet Groves in his office. On a number of occasions, Groves sent Mrs. O’Leary on trips to Oak Ridge, Hanford, and Los Alamos to meet with Project officials and sometimes even used her as a courier to carry top secret information.
O’Leary passed away on October 12, 1983.