The American Legion is a national organization of war-time military veterans. To be eligible, a person must have served at least one day of active duty during a period of declared war, as defined by the US Congress. A person need not have actually served in a combat zone, but must have been on active duty status at least one day during a recognized period. Currently, these dates are:
| War Era | From | Until |
| Persian Gulf | Aug 2, 1990 | open |
| Persian Gulf | Dec 20, 1989 | Jul 31, 1990 |
| Panama/Grenada | Aug 24, 1982 | Jul 31, 1989 |
| Viet Nam | Feb 28, 1961 | May 7, 1975 |
| Korea | Jun 25, 1950 | Jan 31, 1955 |
| World War II* | Dec 7, 1941 | Dec 31, 1946 |
| World War I | Apr 6, 1917 | Nov 11, 1918 |
* Merchant Marines from WWII are eligible, but the dates of service must be between Dec 7th, 1941, and Aug 15th, 1945.
Service members from the Army, Navy, Air Force, Marines, and Coast Guard are eligible in any listed time period, and members of the Merchant Marines during WWII may be eligible subject to the date restrictions given below the table.