When Marvel put together Ultimate Spider-Man and someone came up with the idea of having Principal Coulson, they said, "Do you want to do the voice?" I thought, "I have to do the voice!" Because I have a daughter and we watch some cartoons, I couldn't bear the idea of tuning in and hearing somebody else's voice.

The technology actually seemed to come at just the right time to make the Hulk - Mark Ruffalo was really able to play both characters.

When Marvel put together Ultimate Spider-Man and someone came up with the idea of having Principal Coulson, they said, "Do you want to do the voice?" I thought, "I have to do the voice!" Because I have a daughter and we watch some cartoons, I couldn't bear the idea of tuning in and hearing somebody else's voice.

Joss Whedon and all the writers of 'Iron Man' and 'Thor' found a way to keep Coulson saying something that keeps you guessing. I'm really lucky because a lot of people play agents and don't get nearly as much fun stuff to do.

I think about it, and I realize there's been some version of a Batman or Spiderman or Superman franchise since I was a boy, since before I was a boy.

No matter how tight the shot is, if I'm narrating it too much, there's a barrier between you and the experience, because the process of reading a book, or watching a movie, or watching a play is that you're watching a dream.

What I love about Coulson is that he manages to do that and he manages to wrangle the diva superheroes, and really keep a sense of humor about it. And, you can tell that he really loves his job.