A graduate of Vassar, Julia Hamblet earned a masters degree at Ohio State. Six years later, she was sworn in as the first Marine Corps Women's Reserve Officer Candidate. Commissioned as a First Lieutenant upon completing training, she served first at Camp Lejeune, North Carolina. Promoted to Captain, then Major, she served as Commanding Officer of the Women's Reserve Battalion at Quantico, Virginia. At Cherry Point, North Carolina, she commanded the Aviation Women's Reserve Group, the largest Woman Marine Command in World War II with 2,500 enlisted women and 125 officers.
Discharged at the end of the war, she was called back in 1946 as Director of the Marine Corps Women's Reserve. She was the youngest director of any of the American women's services. In 1948, she accepted a regular commission as Major, one of the first three women officers commissioned as regular officers in the USMC. Promoted to Lieutenant Colonel, she planned and established the first Women's Organized Reserve Units in the country. Other assignments included Assistant Personnel Officer, Fleet Marine Force, Pacific in Pearl Harbor and Commanding Officer of Women's Officer training at Quantico. In 1953, she was promoted to Colonel and was appointed Director of Women Marines, a position she held for six years. She subsequently became Military Secretary to the Commander-in-Chief, Allied Forces, Southern Europe, and retired in 1965 following Command of Women's Recruit Training at Parris Island. She was awarded the Legion of Merit.
Miss Hamblet worked for the U.S. Office of Education from 1965 to 1978 in elementary and secondary education programs, the Right to Read Program and managed the Guaranteed Student Loan Program in four northwestern states. She moved to Alexandria, Virginia, where her volunteer work included being a board member of the Alexandria Red Cross and the Alexandria Y.W.C.A. In 1986, she moved to Williamsburg, Virginia.