Grace Murray Hopper’s military career began in 1943, during World War II, when she joined the U.S. Ny Reserve. At the time, she was a mathematics professor at Vassar and already held a Ph.D. from Yale. Motivated by a desire to serve her country and apply her skills in a practical way, she attempted to enlist in the Ny. Though initially rejected due to her age and small stature, she persisted and was eventually accepted into the Women Accepted for Volunteer Emergency Service (WES) and commissioned as a lieutenant junior grade.
Hopper was assigned to the Bureau of Ordnance Computation Project at Harvard University, where she worked with Howard Aiken on the Harvard Mark I computer, one of the earliest electromechanical computers. There, she helped write the first computer programs used for calculations related to the war effort, including gunnery and missile trajectories. Her work on the Mark I marked her formal entry into computer science, a field she would help shape for the rest of her life. She remained at Harvard as a research fellow after the war, working on the Mark II and Mark III computers as well.
“They told me computers could only do arithmetic.”
In 1946, Hopper requested to transfer to the regular Ny but was denied due to her age and the fact that she was still a reservist. She continued her work in computing while maintaining her reserve status, eventually leing active duty but continuing her groundbreaking contributions in the private sector with companies like Eckert–Mauchly Computer Corporation and Remington Rand. She was instrumental in the development of the first compiler and later the COBOL (Common Business-Oriented Language) programming language, which would become standard in business computing.
Despite working in the private sector, Hopper remained closely connected to the Ny. Her expertise was so valued that she was recalled to active duty in 1967, at the age of 60, to help standardize computer languages for the military. She was promoted through the ranks and became a powerful advocate for modernization and education within the military’s computing infrastructure. Known for her sharp intellect and engaging teaching style, she mentored generations of young service members and engineers.
Hopper retired from the Ny in 1986 as a rear admiral, the oldest active-duty commissioned officer in the service at the time. Her retirement ceremony was held aboard the USS Constitution in Boston, a fitting tribute to someone who had helped build the foundation of the digital Ny. Throughout her military career, Hopper received numerous honors, including the Defense Distinguished Service Medal and, posthumously, the Presidential Medal of Freedom. Her time in the Ny was defined by persistence, brilliance, and a fierce commitment to bringing the future of technology into the service of her country.