Brewer was commissioned a second lieutenant in the
United States Marine Corps 1952. Her first assignment was at the
Marine Corps Air Station El Toro,
California, where she served as a communications watch officer until June 1953. She was then transferred to
Brooklyn, New York, for a two-year tour as Inspector-Instructor of a Women Marine Reserve unit. From September 1955 until June 1958, then Captain Brewer served successively as Commanding Officer of the Women Marine companies at
Norfolk, Virginia, and
Marine Corps Base Camp Lejeune,
North Carolina. During the 18 months following, she was a platoon commander for woman officer candidates at
Marine Corps Base Quantico, Virginia, during summer training sessions, and for the balance of the time, a woman
officer selection officer with headquarters in
Lexington, Kentucky. Transferred to
Marine Corps Base Camp Pendleton, California, in November 1959, for duty with the Commissioned Officers Mess (Open), Brewer was promoted to major in September 1961 and in April 1963 returned to Quantico to serve as executive officer and later as commanding officer of the Woman Officer School. By 1966, she was the Public Affairs Officer for the 6th Marine Corps District,
Atlanta, Georgia as lieutenant colonel. Brewer served as Deputy Director of Women Marines, at Headquarters Marine Corps, from March 1968 to March 1971. She was promoted to colonel in 1970. Reporting to Quantico, she assumed duty as Special Assistant to the Director, Marine Corps Education Center. She became Chief of the Support Department, Marine Corps Education Center in June 1972, serving in this capacity until she was selected as the seventh Director of Women Marines on February 1, 1973 until 1977. On July 1, 1977, then Colonel Brewer assumed duty as Deputy Director of the Division of Information, Headquarters Marine Corps, when the Director of Women Marines' office was disbanded because of the strides made in integrating women into an expanded role in the Corps. For meritorious service as the Director of Women Marines, she was presented the
Legion of Merit by the
Commandant of the Marine Corps on June 30, 1977. While serving as the Deputy Director of the Division of Information, Headquarters Marine Corps, Brewer was nominated to the post of Director of the Division of Information, which required a general rank. At the time, the Marine Corps did not allow women to hold the a general rank, President Carter made a special nomination to the grade of
brigadier general that was approved by both house of Congress. She was appointed to that grade and assumed duty as Director of Information on May 11, 1978, at which time she became the first female general officer in the United States Marine Corps. After Brewer reorganized the division, the Division of Information was redesignated as the Division of Public Affairs, and Brigadier General Brewer's title was changed to Director of Public Affairs. Brewer retired in 1980. ==Later years and death==