If you said he'd been acting aggressively, I'd say that he had been playing bully with his chips stack.

If you thought he had absolute crap, then going all in here was a good move. Put the pressure on him. If he has diddly, he'll probably fold and you're only an underdog to PP's and another A. Sucks this time that he actually had a hand.

On the other hand, if he's been playing pretty tight (which you said he hadn't, or I thought you'd implied it), then you should respect his raise.