"I've watched him over a couple of years, he was a transfer target at West Brom and I know what kind of player he was. For me when an opportunity arose it was the obvious thing to do," Hodgson told reporters.
"If any player prefers to play for another team other than England they are welcome to do so. If our national team is not motivation, we do not want them in there. I automatically assumed that when I give an England Under-19 player a chance, I expect him to cycle there if necessary.
"I spoke to him, of course, before he joined up. I made it clear to him that we were interested in him, but only if he was interested us and he assured me that. He's played for England at all levels so, it seems to me fairly obvious that if you decide you want to play for England Under-19s and you want to play for England Under-21s you're very happy to accept a call-up to the first national team."
"It seems pretty obvious to me that's where you want to play, but then, perhaps I'm too simple. He's told me that's what he wants to do."
Zaha is expected to be a transfer target for a number of Premier League clubs in January.