There are a few random Americans in the United States who, when traveling/living overseas for any length of time, will need a “criminal record check”. For people who are not from the US, this is a relatively easy thing to come by. They just walk in to their local police office, request it, and that’s it.
It’s a bit more difficult in the US as most people never request it and most in an administrative capacity have any idea how you go about getting one, especially at the embassies of foreign governments. It’s actually not that hard and most of what you’ll need is time. Surprisingly, the US State Department outlines the process quite well and defines the two types which are a local police check and a national FBI check.
I have no idea when you need one over the other and there really doesn’t seem to be a consistent format for the local police checks, but those are the easiest as you just walk in, request it, scratch your and the officer’s head as to what format it’s supposed to take and then walk out. While you’re there though, you might want to look in to getting a set of fingerprints as those will be needed for the FBI check.
This FBI check is a bit more intense, although a great deal more thorough and formulated. You send in a formal request to the FBI with a fee along with the fingerprints. Up to eight weeks later they send you back the background check. Problem is, you’re bound to need what you get back, “authenticated”. Normally that means sending it in to a state office for the almighty, 19th century throwback known as the (fucking) apostille. But, given that this is a federal-level document, I believe you have to send it in for federal-level certification which you do here and will take an additional eight weeks.
The catch in all of this is that you obviously need to do it long before you need it and once overseas, you might find it very hard/expensive to request all of this. So, all I can say is, it ain’t a perfect system, but this is apparently how you do it. Oh, and you’ll most likely need an official, certified translation of everything as well for the country where you’re going to. Yay.