He began his teaching career at Rutgers University, where he earned the rank of Professor of History and also served for a period as Vice President for Academic Affairs.

Martin helped to found the Papers of Thomas Edison project at Rutgers University and for a few years served on its board of advisers.

Martin was serving on the advisory board of editors for the Critical Historical Encounters book series sponsored by Oxford University Press.

His later research interests focused on military, social, and political aspects of early American history, especially the Revolutionary era and beyond.

Martin's later writing projects included The Remarkable Revolution: How the United States Avoided Becoming a Military Dictatorship, 1775-1787 (tentative title, with Oxford University Press), as well as a volume on Han Yerry Doxtader and the Iroquois Indians titled American Warrior: Han Yerry Doxtader, the Battle of Oriskany, and the Decline and Fall of the Six Nations of Iroquois Indians.