Mary Agnes Hallaren (May 4, 1907 – February 13, 2005) was an American soldier, the director of the Women's Army Corps at the time that it became a part of the United States Army. As the director of the WAC, she was the first woman to officially join the U.S. Army. (Some women had fraudulently joined the U.S. Army during other wars by pretending to be men.)
Born in Lowell, Massachusetts, the daughter of John Joseph Hallaren and Mary Kenney Hallaren. She graduated in 1925 from Lowell High School (Lowell, Massachusetts) and attended Boston University and graduated from Lowell State Teachers College now University of Massachusetts Lowell. She taught junior high school for 15 years in Lexington, Massachusetts, spending her summers on vigorous walking tours, which she called vagabonding throughout the United States, Mexico, Canada, and Europe.
In 1942 Hallaran entered the Women's Army Auxiliary Corps, which later became the WAC. A recruiter asked the diminutive Hallaran (she barely stood five feet tall), how someone of her size could help the military. She replied, "You don't have to be six feet tall to have a brain that works."
In 1943, as a captain, she commanded the first women's battalion to go overseas. She served as director of WAC personnel attached to the 8th and 9th Air Forces, and by 1945, as a lieutenant colonel, she commanded all WAC personnel in the European theater.
By 1947, Hallaren was a full colonel, and was appointed director of the entire WAC. On June 12, 1948, when the WAC was officially integrated into the Army, she became the first woman to serve as a regular Army officer (there had been female members of the Army Medical Corps since 1947).
She served as director until 1953, then retired from the army in 1960, having been awarded the Legion of Merit, the Bronze Star and the Army Commendation Medal. She served in the United States Department of Labor as director of the Women in Community Service division. She retired in 1978, but continued to serve in an advisory capacity.
In the 1990s, she was a leading proponent of the Women's Memorial at Arlington National Cemetery, which was dedicated in 1997. She was elected to the National Women's Hall of Fame in Seneca Falls, New York, in 1996 and was featured by Tom Brokaw in his book "The Greatest Generation."
She died at the Arleigh Burke Pavilion, an assisted living facility for retired military personnel in McLean, Virginia.