A Station Eight Fan Web Site
I want to repost this question like you suggested:
I'm interested in your thoughts (and possibly Brandon Vietti's and Jamie Thomason's as well, if possible) on the casting process for the voices of the main characters of Young Justice. What was/is it that the main cast - Jesse McCartney, Khary Payton, Nolan North, Stephanie Lemelin, Danica McKeller, and Jason Spisak - bring to their respective characters that you, Vietti, and Thomason were looking for? In another question, you answered that the members of Young Justice were chosen based on a variety of factors (i.e. personality, dynamics, etc.). How did that play out in the casting process?
I'm not going to attempt to speak for Brandon or Jamie, though I'd lay odds our thoughts on this subject are at least similar. But I'll take the original six leads and - one by one - give a little bit about what I remember from ... nearly a decade ago.
B-01 Jesse McCartney as Robin - Jesse was one of the last actors cast, mostly because we were having trouble finding a Robin, and Jesse was part of a second (or third?) round of auditions that we went through in our search. We were looking for someone who could bring the fun of our thirteen-year-old kid. Who could do that gleeful laugh and pull off words like "whelmed" ... and still bring the serious when we needed it. Jesse could do all that. Was that because he himself had been a pro since he was a kid? I don't know. All I can tell you is he brought all those qualities.
B-02 Khary Payton as Aqualad - Khary actually had a strike against him, going in, because he played Cyborg on Teen Titans. As we wanted to distinguish ourselves from that series and Justice League Unlimited, we weren't too inclined to use regulars from those series as regulars in ours. But Khary's audition just nailed it, leaving us no choice. (Thank God.) He instantly "got" the character and instantly mastered that combination of wistful steadfastness, maturity and leadership we were looking for, without making the character suddenly older than his sixteen years. Plus he really nailed that feeling of English-as-a-second-language that we wanted our Atlantean to have.
B-03 Jason Spisak as Kid Flash - As Jamie often said, no one was better than Jason at bringing out his inner douche. Wally had to be both obnoxious and lovable. He had to be smart and a dope. He had to be Robin's best friend and a bit of a pain. Enthusiastic and insecure. Blustering and vulnerable. Jason was able to bring all those contradictions to life.
B-04 Nolan North as Superboy and Superman - This was tricky, too, as we needed someone who could play both Superman (age 33) and his clone Superboy (age 16). Nolan does an amazing job at playing both characters, making them sound distinct and yet genetically the same. Conner had to start out angry but have somewhere to go. There had to be heart and depth beneath his hardened exterior. Nolan did all that.
B-05 Danica McKellar as Miss Martian - We were actually looking for someone who had a bit of experience as a sitcom actress to play M'gann (and eventually Megan Wheeler and Marie Logan). Someone who understood those rhythms but could transcend them, as well. Someone who could play the insecurity that comes with hiding big secrets from the people she's closest to, but also be a bad ass when necessary. Someone who would be unafraid to be soft and (traditionally) feminine and not be hamstrung by that.
B-07 Stephanie Lemelin as Artemis - Artemis needed edge. She was the tough girl, particularly in contrast to Miss Martian. But underneath it, she - like most of the other characters - had some vulnerability and a lot of insecurity because of the secrets she too was hiding. Stephanie brought that edge.
And, of course, all six brought - in addition to their acting skills and intuitive understanding of the character - certain vocal qualities that just felt like they fit the designs of the characters.