Members of the Marine Corps League join together in camaraderie and fellowship for the purpose of preserving the traditions and promoting the interests of the United States Marine Corps. The Marine Corps League perpetuates the traditions and spirit of ALL Marines and Navy FMF Corpsmen, who proudly wear or who have worn the eagle, globe and anchor of the Corps. It takes great pride in crediting its founding in 1923 to World War I hero, then Major General Commandant John A. Lejeune. It takes equal pride in its Federal Charter, approved by An Act of the Seventy-Fifth Congress of the United States of America and signed and approved by President Franklin D. Roosevelt on August 4, 1937. The League is the only Federally Chartered Marine Corps related veterans organization in the country. Since its earliest days, the Marine Corps League has enjoyed the support and encouragement of the active duty and Reserve establishments of the U. S. Marine Corps. Today, the League boasts a membership of more than 76,000 men and women, officer and enlisted, active duty, Reserve Marines, honorably discharged Marine Veterans and qualified Navy FMF Corpsmen and is one of the few Veterans Organizations that experiences increases in its membership each year.

The Marine Corps League is headed by an elected National Commandant, with 14 elected National Staff Officers who serve as trustees. The National Board of Trustees coordinates the efforts of 49 department, or state, entities and the activities of over 1100 community-based detachments located throughout the United States and overseas. The day-to-day operations of the League are under the control of the National Executive Director with the responsibility for the management and direction of all programs, activities, and affairs of the Marine Corps League as well as supervising the National Headquarters staff.

The prime authority of the League is derived from its Congressional charter and from its annual National Convention held each August in different major U.S. cities throughout the nation. It is a not-for-profit organization within the provisions of the 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.