John S. Bersey was the Michigan National Guard's Adjutant General from June 23, 1915 to August 8, 1940. He retired from the Adjutant General's office with the rank of Colonel after serving more than 25 years in that capacity. At retirement, Col. Bersey had 51 years service as an active member of the Michigan National Guard.

Bersey enlisted as a private, Company A, Fourth Infantry, December 16, 1889. He was promoted to Corporal and then Sergeant before the end of his three year term of service. He re-enlisted and was promoted to First Sergeant and then Regimental Sergeant Major, Fourth Infantry.

In October 1894, Bersey was commissioned First Lieutenant. He served on Federal duty during the Spanish-American War with the 31st Michigan Voluneer Infantry from May 1898 to May 1899. After returning to the Fourth Infantry, he was promoted to Captain. Assigned to First Battalion, First Infantry, he was promoted to Major and then Lieutenant Colonel.

Appointed as the Adjutant General of Michigan with rank of Colonel, June 23, 1915, Bersey served as Draft Executive for Michigan during the World War. He graduated from Army War College, 6-I Course, 1924 and Garrison School for Officers, U. S. Army, at Fort Wayne, Michigan, in 1907 (four-year course).