Former Private, Company A, 7th US Cavalry. At the time of his death, he was a civilian employee of the Fort Meade Quartermaster Department, serving as a teamster.
Born in Edinburg, Scotland. He had a second enlistment of August 29, 1871 at the age of 22 in Louisville, Kentucky by Lieutenant W. W. Cooke. In the Diary of Dr. James M. DeWolf (of the 7th Cavalry), the entry for June 6, 1876 relates: a man accidently shot through calf of leg coming out on back of right foot, the pistol accidently went off while mounting the horse. In Mark Kellogg's diary for June 6 is this entry: Private McWilliams accidently shot himself with a revolver today; ball took effect calf leg ran down tendon and lodged just under skin top of foot, flesh wound, lay him up for a month. This happened on the west fork of O'Fallon's Creek, Montana Territory. As a result, he missed the Battle of the Little Big Horn, and was evacuated back to Fort Abraham Lincoln on the steamboat Far West, which was bringing supplies to the troops in the field. He was discharged on August 29, 1876 at Fort Rice, North Dakota, upon expiration of service as a Private of good character. He reenlisted immediately and was transferred to Company A. He had blue eyes, brown hair, a fair complexion, and was 5 feet, 5 1/2 inches tall.
From the 1880 census for Fort Meade, South Dakota: McWilliam, David, age 29, white, male, Private of Cavalry, born Scotland, both parents born Scotland; Annie, age 34, wife, born Kentucky, parents born "don't know"; James, age 5, son, born Louisiana. Note: after his death, his widow Annie married Maximilian Goetz. Annie is buried beside Max Goetz in the Fort Meade Cemetery, Sturgis, SD.