Was a cadet in the US Naval Academy. Graduated in 1866. Was a tax revenue collector with his father in the Missouri 4th District. Became a tobacconist. Moved to Denver in 1883 and became a respected breeder in Jersey cattle. Had a ranch near Henderson Colorado. Lived in Denver on Court Place - 1663 Court Place with his second wife Ada (Buffum) Stewart of Louisiana, Missouri. It was said he had the best Jersey Cattle in the state. In 1889 consumption took his life and his remains were brought back to Louisiana, Missouri to be buried with his son and first wife and parents.

"Death of a Prominent Citizen
David A Stewart, a Prominent Cattleman, Passes Away
David A Stewart died at No. 1663 Court Place at 1 o'clock Sunday Morning, January 27 from the effects of a hemorrhage of the lungs.
Mr. Stewart was in his 42nd yr. His native State was Missouri. He entered the Naval School at Annapolis in 1863, graduating in 1867 and serving in the United States Navy for two years following mostly on the coast of South America. Resigning in 1869 he became a cashier of a bank in Macon, Missouri. In 1881 President Arthur appointed him Collector of Internal Revenue for the Fourth District of Missouri. Mr. Stewart came to Colorado in 1884 and has since been engaged in the raising of Jersey Cattle. He was one of the best known cattleman in the State.
Mr. Stewart leaves a wife, Mrs. Ada Buffum Stewart, formerly of Missouri and two sisters in this state. Mrs. D M Draper of Denver and Mrs. John Jordan of Barr.
Abet four years ago Mr Stewart was married to Miss Ada Buffum the daughter of Colonel GA Buffum of Louisiana (Missouri) and whos mother was a sister of the famous Washburns, whose names have long been famous in American History.
Colonel Buffum accompanied by the Bereaved widow started with the remains for Louisiana (Missouri) on last evening's Burlington train.
Mrs. Stewart has the sympathy of a large circle of friends in her sad affliction."