Gallagher received a Bachelor of Arts from Adams State College in 1972. He then did graduate study in history at the University of Texas at Austin, receiving a Master of Arts in 1977 and a Ph.D. in 1982. He was a professor of history at Pennsylvania State University from 1986 to 1998, when he joined the faculty at the University of Virginia.

He is the presenter of an Audible series of lectures entitled The American Civil War. An in depth look at the American Civil War. These are currently available on Audible as a series of read lectures which go into great detail on the Civil War. He both wrote and read the lecture series as part of The Great Courses. The series has 48 lectures, each averaging about 30 minutes, meaning more than 24 hours of lectures in total. This is presented exclusively for Audible books.

In 2021, Gallagher received The Lincoln Forum's Richard Nelson Current Award of Achievement.^[4]

Authored Books edit

• with Joan Waugh: The American War: A History of the Civil War Era. State College, Pennsylvania: Spielvogel Books, 2015^[5]
• Becoming Confederates: Paths to a New National Loyalty. Athens: University of Georgia Press, 2013.
• The Union War. Cambridge, Mass.: Harvard University Press, 2011.^[6] (Winner of 2012 Tom Watson Brown Book Prize, 2012 Laney Prize, 2011 Eugene Feit Award in Civil War Studies; The New York Times Book Review Editors’ Choice)
• Causes Won, Lost, and Forgotten: How Hollywood and Popular Art Shape What We Know about the Civil War. Chapel Hill: University of North Carolina Press, 2008.
• Lee and His Army in Confederate History. Chapel Hill: University of North Carolina Press, 2001.
• The American Civil War: The War in the East 1861-May 1863. Oxford: Osprey Publishing, 2000. (History Book Club selection)
• Lee and His Generals in War and Memory. Baton Rouge: Louisiana State University Press, 1998. (Winner of 1998 Fletcher Pratt Award; History Book Club selection)
• The Confederate War. Cambridge, Mass.: Harvard University Press, 1997. (Winner of 1998 Laney Prize and finalist for 1998 Lincoln Prize [shared the prize with three other books]; History Book Club selection)
• Stephen Dodson Ramseur: Lee's Gallant General. Chapel Hill: University of North Carolina Press, 1985. (History Book Club Selection)

Edited books edit

• The Antietam Campaign. University of North Carolina Press. 1999. ISBN 9780807824818.
• Three Days at Gettysburg: Essays on Confederate and Union Leadership. Kent State University Press. 1999. ISBN 9780873386296.
• Fighting for the Confederacy: The Personal Recollections of General Edward Porter Alexander. University of North Carolina Press. 2000. ISBN 9780807882344.
• with Alan T. Nolan: The Myth of the Lost Cause and Civil War History. Indiana University Press. 2000. ISBN 0253338220.
• The Wilderness Campaign. University of North Carolina Press. 2006. ISBN 9780807857854.
• Chancellorsville: The Battle and Its Aftermath. University of North Carolina Press. 2012. ISBN 9780807835906.

• Gary W. Gallagher on C-SPAN