John Daniel Leinbach Hartman (August 9, 1865 – July 29, 1953) was a United States Army officer in the late 19th and early 20th centuries.

He was originally stationed at Fort Assinniboine and participated in the Ghost Dance War, including the Battle of Wounded Knee.

He served as a quartermaster of the Blue Army at the Connecticut Maneuvers in 1912, and he was in charge of manufacturing at Schuylkill Arsenal around the same time.

[1] Hartman was promoted to the rank of brigadier general on October 1, 1918, and he held command over a training camp in Waco, Texas.

[3] Hartman married Helen Canby Ward (November 16, 1875 – February 11, 1954) while on frontier duty early in his career.