Hyman has a bachelor's degree from the University of California, Los Angeles (1948) and an M.A. (1950) and Ph.D. (1952) from Columbia University. During World War II Hyman served in the Marines as a gunner in the South Pacific.
Hyman was an instructor in modern history at City College (1950–52); assistant professor of history, Earlham College, 1952–55; visiting assistant professor of American history, UCLA 1955- 56; associate professor of American history, Arizona State University, 1956–57; professor of history, UCLA 1963-68; William P. Hobby Professor of History, Rice University, 1968--
Honors and awards
He has been a Ford Foundation Fellow, a Senior Fulbright Lecturer, an Organization of American Historians Lecturer, and a judge for the Pulitzer Prize and the Littleton-Griswold prize of the American Historical Association.
- Era of the Oath: Northern Loyalty Tests during the Civil War and Reconstruction (University of Pennsylvania Press, 1954, reprinted, Hippocrene Books, 1978).
- To Try Men's Souls: Loyalty Tests in American History, (University of California Press, 1959, reprinted, Greenwood Press, 1981). online
- (With Benjamin P. Thomas) Stanton: The Life and Times of Lincoln's Secretary of War (Knopf, 1962, reprinted, Greenwood Press, 1980). online
- Soldiers and Spruce: The Loyal Legion of Loggers and Lumbermen, the Army's Labor Union of World War I (University of California Press, 1963).
- A More Perfect Union: The Impact of the Civil War and Reconstruction on the Constitution (Knopf, 1973). online
- Union and Confidence: The 1860s (Crowell, 1976), survey with emphasis on business history online
- With Malice toward Some: Scholarship (Or Something Less) on the Lincoln Murder (Abraham Lincoln Association, 1978) online
- Equal Justice Under Law: Constitutional Development, 1835-1875 (New American Nation Series) with William Wiecek ISBN 978-0-06-014937-6
- Quiet Past and Stormy Present?: War Powers in American History (American History Association, 1986), pamphlet
- American Singularity: The 1787 Northwest Ordinance, the 1862 Homestead- Morrill Acts, and the 1944 G.I. Bill (University of Georgia Press, 1986). online
- The Reconstruction Justice of Salmon P. Chase: In Re Turner and Texas v. White (University Press of Kansas, 1997).
- Oleander Odyssey: The Kempners of Galveston, Texas, 1854-1980s (Kenneth E. Montague Series in Oil and Business History) ISBN 978-0890964385 (Texas A & M University Press, 1990).
- Craftsmanship and Character: A History of the Vinson & Elkins Law Firm of Houston, 1917-1997 (Studies in the Legal History of the South) ISBN 978-0820319735 (University of Georgia Press, 1998).
He has been editor, contributor, or joint author:
- The Radical Republicans and Reconstruction Policy, 1861-1870 (Bobbs- Merrill, 1966), primary sources
- New Frontiers of the American Reconstruction (University of Illinois Press, 1966), scholarly essays
- (With Leonard W. Levy) Freedom and Reform: Essays in Honor of Henry Steele Commager (Harper, 1967).
- (With H. C. Allen and others) Heard 'round the World: The Impact Abroad of the Civil War (Knopf, 1969).
- (author of introduction) Carleton Parker, The Casual Laborer and Othe Essays (new edition of 1919 original, University of Washington Press, 1972).
- (author of introduction, with wife, Ferne Hyman) The Circuit Court Opinions of Salmon Portland Chase (new edition of 1875 original, Da Capo Press, 1972).
- (author of introduction) Sidney George Fisher, The Trial of the Constitution (new edition of 1862 original, Da Capo Press, 1972).
- (author of introduction) Edward McPherson, The Political History of the United States of America during the Great Rebellion, 1860-1865 (new edition of 1865 original, Da Capo, 1972).
- (With Hans L. Trefousse) McPherson, Handbook of Politics, six volumes, new edition of 1894 original, Da Capo, 1972-73.
- (With Trefousse) McPherson, The Political History of the United States of America during the Period of Reconstruction, new edition of 1871 original, Da Capo, 1973.
- (With Kermit L. Hall and Leon V. Sigal) The Constitutional Convention as an Amending Device, American Historical Association/American Political Science Association, 1981.
- Editor, with Stuart Bruchey, of the "American Legal and Constitutional History Series," Garland Publishing, 1986-87.
- Member of board of editors, Reviews in American History, 1964--, Ulysses S. Grant Association, 1968—American Journal of Legal History, 1970--, and Journal of American History, 1970-74.
Bodenhamer (2012) says, "The best guide to the constitutional changes brought by the Civil War and Reconstruction is Harold Hyman, A More Perfect Union: The Impact of the Civil War and Reconstruction on the Constitution (1973). Mayer (2001) says Hyman, "wrote the definitive work on loyalty tests throughout American history."
- "Happy Birthday, Dr. Hyman!". http://ricehistorycorner.com/. Rice University. Retrieved 22 January 2015. External link in
- "Harold M. Hyman". History News Network. Archived from the original on 18 August 2013. Retrieved 12 September 2012.
- "Hyman Collection". Prairie View A&M University. Archived from the original on 27 February 2013. Retrieved 12 September 2012.
- David J. Bodenhamer, (Oxford University Press, 2012) p 251
- Kenneth R. Mayer, With the Stroke of a Pen: Executive Orders and Presidential Power (2001) p 153