The National Guard of the United States is made up of two components; the Army National Guard and the Air National Guard. The age requirements are the same for both branches, and are set forth under Title 10 of the United States Code. The National Guard observes both a minimum age limit and a maximum age limit. Waivers are very rarely granted for those who are overage and never for those who are underage.
Minimum Age Requirement
To join the Army or Air National Guard, you must be at least 18 years of age. However, if you have your parent's signed consent, you may join at the age of 17. Waivers are not granted for those who do not meet the minimum age requirements.
Maximum Age - Non-Prior Service - Army National Guard
If you have never served in the military before, the maximum age limit for joining the Army National Guard is 42. However, some states have lower age maximums depending on the location. Waivers are never approved for enlisted members, but certain officer career fields, such as physicians and attorneys, may receive waivers if they are over the age limit and their chosen career field is under-manned.
Maximum Age - Prior Service - Air National Guard
If you have never served in the military before, you can join the Air National Guard as an enlisted member up to your 40th birthday. For officer candidates, you must be commissioned by your 35th birthday. This age is mandated by the federal government and each individual state. The requirement is never waived for enlisted members, but can be waived for officer candidates who wish to enter an under-manned career field.
Maximum Age - Prior Service
If you have prior military service in any branch, you must be able to complete 20 years of service by your 65th birthday. For example, if you previously served for 13 years in the Navy, you must be able to complete the remaining seven years for a good retirement before you turn age 65. Therefore, you can enlist prior to your 58th birthday. Waivers are not granted for this age limit as National Guard retirement ages are mandated by the federal government.