He served briefly in Company A, 4th Michigan Infantry Regiment before receiving appointment to the United States Military Academy (West Point).

Bates served on frontier duty at posts in western states including Kansas, Nebraska, and Wyoming and took part in expeditions during the American Indian Wars.

During the Spanish–American War, he was promoted to temporary brigadier general and was assigned as U.S. military attaché in London and Paris.

In retirement, Bates was a resident of Washington, D.C., and was called on to perform public service including assisting the American Red Cross during its response to the 1906 San Francisco earthquake and representing the United States during Pan-American Conferences on international finance and monetary policy.

[1] In May 1861, Bates enlisted in the Union Army for the American Civil War, joining Monroe's Smith Guards, which organized and trained at an encampment in Adrian, Michigan.

[4] During his academy years, Bates was one of Elizabeth Bacon's suitors, but she married George Armstrong Custer in 1864.

[4] In January 1869, Bates was promoted to captain, and performed frontier and scouting duty at Fort McPherson, Nebraska until August 1869.

[4] Bates joined the United States Volunteers for the Spanish–American War and was assigned as U.S. military attaché in London, where he served from March 1898 to May 1899.

[4] In July 1899, Bates was promoted to permanent brigadier general and assigned as the Paymaster-General of the United States Army, succeeding Asa B. Carey, and he served until January 1904.

[6] In May 1906, he accepted a request from William Howard Taft, the United States Secretary of War to assist the accounting department of the American Red Cross as it provided disaster relief following the San Francisco earthquake.

[8][10][11] In September 1898, Félix Faure, the president of France, conferred on Bates the Legion of Honor (Officer) in recognition of his service as U.S. military attaché in Paris.

[19] McCorkle was a favorite niece of the Morgans, and as a result she inherited a substantial portion of their wealth when they died in the mid-1880s.