Daniel Radcliffe Charms Us Over in a Deathly Hallows Interview

How producers knew he'd be perfect for every Potter film: 

Daniel Radcliffe:  [laughs]  I don't know.  I think they probably saw my mother and thought, 'Oh this boy isn't going to grow that much.' Because she's like five foot and my grandmother is four foot nine, so they presumably just thought, 'Ah, he's not going to get too tall for the role, that's for sure.'  And then, to be honest with you, I think studios have a reputation for being quite cutthroat.  And I don't think they have been on Potter at all. There was definitely a sense of loyalty and it there was never a sense that we were going to be screwed over by studio in any way. They were always very, very supportive and I think they always realized, particularly in the early days that they were dealing with young kids, who's hearts would be broken if suddenly they said, 'We're replacing you.'  You know? 

I think that's why the casting process took so long, because they wanted to find people that would not only be right for the first film, but also sort of durable enough to last, hopefully, for quite a few years.  And it was certainly talked about from all our points of view. I mean, I had moments where I thought, 'Well, maybe after three, that would be the time to walk away because that will give somebody else a run before the end.' I know Emma [Watson] was sort of deliberating to sort of stay or go before she did number six.  So we've all had those moments, but ultimately we all thought we're so lucky to get these parts.

Changing directors from the beginning to the end:

Daniel Radcliffe:  Yeah, I think it was great to be honest with you, because I remember when Chris [Columbus] told me he was leaving after number two, I was very upset and I thought, 'Oh no, that's a terrible thing.' But actually, it proved the best thing for the series because it opened it up to different creative ideas and different people came on board, and it made the series...and also I think the fact that Alfonso [Cuaron] came along to the film was not just for him, but really, really smart from our producers, particularly David Heyman, who was very instrumental in that, because it gave...he'd just directed Y Tu Mama Tambien and it gives you a bit of...for such a mainstream movie franchise, it gives you a bit of weight with the critics, to have somebody who's had such an indie, you know...suddenly working on the film.  [laughs] 

So I think that made people see us in a slightly different light. And I think the fact that David Yates got the job on number five was fantastic because it shows that we're not afraid of taking risks.  Because a lot of people saw it as a risk.  I mean, I think the thing that sold David to us all was State of Play, his TV series, State of Play.  Because if you watch that, it's over six episodes, and the level of storytelling is amazing.  And that's what you need for a Potter film. And I've always said about David, that it's like he can see the whole film in one frame in front of him. That's his great advantage as a filmmaker, is his ability to tell stories so, so well.

I think it was vital that they changed directors, but once we got to...it was interesting because once David had done number five and then it looked like he was going to do number six...I think you have to have the same person do seven as did six, because that would have been too big a risk.  If somebody had come in and not known what they're doing and not have known the set up of Potter and how everything works...you need somebody who's already familiar with how everything works on Potter to provide a sense of continuity in the films, because six is such a set up for seven.

Jump ahead to:

Multiple Potters and an intimate (yet awkward) dance scene

Why Radcliffe was disappointed by HP6 and how he aimed to fix it