The Marine Corps League was founded by Major General, John A. Lejeune, in 1923 and chartered by an Act of Congress on August 4, 1937. Its membership of nearly 50,000 is comprised of honorably discharged, active duty, Reserve Marines with 90 days of service or more, and retired Marines. It includes officers and enlisted, male and female members.

The Marine Corps League is classified as a veterans / military service organization and was formed for the purposes of promoting the interests of the U.S. Marine Corps; to provide camaraderie and assistance to Marines, as well as to their widows and orphans; and to preserve the traditions of the U.S. Marine Corps. It is a not for profit organization within the provisions of Internal Revenue Service Code 501 (c) (4), with a special group exemption letter which allows for contributions to the Marine Corps League, its Auxiliary and subsidiary units, to be tax deductible by the donor.