A group of twenty officers who served in the American Expeditionary Forces (A.E.F.) in France in World War I is credited with planning the Legion. A.E.F. Headquarters asked these officers to suggest ideas on how to improve troop morale. One officer, Lieutenant Colonel Theodore Roosevelt, Jr., proposed an organization of veterans. In February, 1919, this group formed a temporary committee, and selected several hundred officers who had the confidence and respect of the whole army.
When the first organization meeting took place in Paris in March, 1919, about 1000 officers and enlisted men attended. The meeting, known as the Paris Caucus, adopted a temporary constitution and the name "The American Legion." It also elected an executive committee to complete the organization work. It considered each soldier of the A.E.F. a member of the Legion. The executive committee named a subcommittee to organize veterans at home in the U.S.
The Legion held a second organizing caucus in St. Louis, MO in May, 1919. It completed the constitution and made plans for a permanent organization. It set up temporary headquarters in NY,NY and began its relief, employment and Americanism programs.
"Congress granted the Legion a national charter in September, 1919. The first national convention, held in Minneapolis, adopted a permanent constitution and elected officers to head the organization."