Membership eligibility in The American Legion is based on honorable service with the U.S. Armed Forces between:
- April 6, 1917 and November 11, 1918 (World War I)
- December 7, 1941 and December 31, 1946 (World War II)
- June 25, 1950 and January 31, 1955 (Korean War)
- February 28, 1961 and May 7, 1975 (Vietnam War)
- August 24, 1982 and July 31, 1984 (Lebanon/Grenada)
- December 20, 1989 and January 31, 1990 (Operation Just Cause - Panama)
- *August 2, 1990 until the date of the end of hostilities as determined by the government of the United States (Operation Desert Shield/Desert Storm).
*Because eligibility dates remain open, all members of the U.S. Armed Forces are eligible to join The American Legion at this time.