Kingman was in the same company with some future Marine Corps generals, like for example William H. Rupertus, Allen H. Turnage, Henry Louis Larsen, Keller E. Rockey, Lyle H. Miller and Alphonse DeCarre.

[1][2][3] Captain Kingman was promoted to the temporary rank of major at the end of October 1918 and placed in command of 6th Machine Gun Battalion.

Major Kingman commanded the 6th MG Battalion during the Meuse-Argonne Offensive and subsequently participated with this unit in occupation duties in Germany.

Kingman was ordered back to Quantico base and attended Field Officer's Senior Course at Marine Corps School, graduating in May 1927.

[1][3] Following his return to the States, Kingman was assigned to the Division of Operations and Training within Headquarters Marine Corps in Washington, D.C., and promoted to the permanent rank of major on September 7, 1927.

He was transferred to the Marine detachment aboard cruiser USS Memphis and served within Special Service Squadron in Latin America.

He then served as chief of staff with Department of Pacific and later as executive officer of the 2nd Marine Brigade under command of Brigadier General Clayton B. Vogel.

Kingman also served simultaneously as commanding officer of Marine Corps Base San Diego from March 19 to April 2, 1942.

[1] In May 1942, Kingman was appointed commanding officer of the Fleet Marine Force Training Center at Camp Elliott, California.

Kingman served in this capacity until 27 April 1944, when he was appointed commanding general of Marine Corps Base San Diego.