Major (MAJ) Harold J. O'Neill served in the United States Army and was a member of the 83rd Signal Company, 83rd Infantry Division during World War II.
The 20th New York Infantry Regiment was composed of volunteers from the Turner societies' "United Turner Rifles" of New York City and its vicinity. The regiment was mustered in on 6 May 1861 for service in the American Civil War. The unit participated in the Seven Days Battles, Antietam, South Mountain, the Battle of Fredericksburg, and the Chancellorsville campaign. The unit was mustered out on 1 June 1863.
From the description of Harold J. O'Neill papers on the 20th New York Infantry Regiment, 1860-1863, undated. (US Army, Mil Hist Institute). WorldCat record id: 772462688
