It's really irrelevant
I honestly don't know whether or not he was born in the US, but it doesn't matter. Native Citizenship is legally determined 2 ways, not 1. There is Jus Soli, which the majority of 'birthers' claim is the One Law of The Land. The other, Jus Sanguinis, means that if one or both of your parents is an American, so are you.
Ultimately, and more relevantly, decent art, but crappy animation.