United States Military Biography
You can find biographical sketches of prominent military figures in published biographical dictionaries. The Family History Library has the following:
Bell, William Gardner. Commanding Generals and Chiefs of Staff 1775–1987: Portraits and Biographical Sketches of the United States Army’s Senior Officer. Washington, DC Center of Military History, United States Army, 1987. (FHL book 973 D3bw.) Contains biographical sketches and portraits of men who led the U.S. Army in peace and war. Includes leaders in early wars through the present.
Brown, Russel K. Fallen in Battle: American General Officer Combat Fatalities from 1775. New York, New York: Greenwood Press, 1988. (FHL book 973 M2brk.) Contains brief biographies of generals who were combat fatalities as well as non-combat fatalities. Includes officers wounded in action and captured by hostile forces.
Cullum, George W. Biographical Register of the Officers and Graduates of the U.S. Military Academy at West Point, New York, New York. Third Edition. Nine Volumes. Boston, Massachusetts: Houghton Mifflin, 1891–1950. (FHL book 974.731/W1 M2cu, Volumes 1–7, 9; films 1697285–88.) Includes state of birth and date and place of death of each graduate from 1802 to 1950.
Spiller, Roger J., editor. Dictionary of American Military Biography. Three Volumes. Westport, Connecticut: Greenwood Press, 1984. (FHL book 973 D36da.) Contains brief alphabetically arranged biographies, with birth and death information. Also arranged by military units, persons by birthplace, and entries by conflict and service. Each volume has a bibliography, and there is a short bibliography found at the end of each sketch, as well.
Webster’s American Military Biographies. Springfield, Massachusetts: G & C Merriam Company, 1978. (FHL book 973 D3wb.) Contains sketches of over 1,000 individuals who have contributed to the military history of the United States, including frontier scouts, nurses, explorers, astronauts, and others.