Lejeune, John A(rcher) (1867–1942)

US marine officer. A brilliant combat commander and a reforming commandant, he oversaw the marine corps' conversion in the 1920s from a colonial police agency into a modern expeditionary force. Appointed commandant of the corps in 1920, he developed amphibious doctrine and tactics that were to be applied in the great Pacific campaigns of World War II. He retired in 1929 to become superintendent of the Virginia Military Institute (1929–37).

Lejeune was born in Pointe Coupee Parish, Louisiana. The son of a sugar planter, he graduated from the US Naval Academy in 1888, served in Panama and the Philippines. He commanded marine detachments at sea, and in 1914 led the marine brigade that assisted in the capture of Vera Cruz, Mexico. In 1918, he took command of the 2nd Infantry Division of the American Expeditionary Force and led it in the battles of St Mihiel, Blanc Mont, and the Meuse-Argonne.