As a child, he was inspired by stories from his great-grandfather, Corporal John Langhans, a veteran of the 154th New York Volunteer Infantry.
Dunkelman's American Civil War research focuses on the 154th New York Volunteer Infantry, known as the "Hardtack Regiment".
[2] He has contacted over 1,200 descendants of members of the 154th, locating and copying over 1,700 wartime letters, 250 portraits, 25 diaries, dozens of relics, and several other memoirs and accounts.
In 2015, a collection of Dunkelman and fellow historian Michael J Winey's research was unveiled at St. Bonaventure University in Allegany, New York.
[1] During the tenth annual reunion, held in 1996, attendees raised funds to erect a monument to their ancestors at Chancellorsville, Virginia.