While you are too old to enlist for active duty service in the US army (maximum cut-off age WITH a waiver is 38), there are a number of contract and civil service roles you can fulfill in and around military bases directly for the military.\n\nThe language school (Defense Language Institute) in Monterey, California is always on the look-out for ex-foreign military to teach students foreign language in military environment so long as you have any kind of teaching credentials at all (6 years of university).