Lex was the last of the main characters cast for the Smallville pilot by executive producers Alfred Gough and Miles Millar. Although a younger version of Luthor is used in the series, whomever took the role had to follow the likes of Gene Hackman from the Superman movies and John Shea from Lois and Clark: The New Adventures of Superman.

So there was good reason to feel a bit daunted. But for Rosenbaum, it's simply a case of taking his own best shot.

"I said, 'Michael, if you're going to do this, if you're going to take risks in your life, if you're ever going to amount to anything, this is one of them. Shave your head and do this role,'" he recalls.

"I thought to myself, 'Gene Hackman was brilliant, but let's not do Gene Hackman. Let's do what Michael Rosenbaum can do and hopefully people will appreciate it.' I just went for it and did my own take on it. I had no idea if people would like it. I went in the audition and gave a read and I thought it was a good read, and the next thing you know they made me an offer. And then I'm shaving my head and I'm playing Lex Luthor."

Gough says that a key was Rosenbaum avoided playing Lex like a "Dr. Evil character."

"It was trying to capture the right combination of humor, danger and charm," Gough says. "A young Michael Keaton was pretty much what we were looking for.

"Michael came in very early in the process, and we didn't respond to him too much at that point. But then he came back and did the scene in the pilot at the mansion where Clark returns the keys. And Michael just blew the doors off the scene. He totally inhabits the character. It was a case where it was the right actor for the right role. He's really fun to write for and really fun to watch."

Smallville quickly became a hit for The WB, and the show - which casts the Superman characters in their formative years - succeeds where comics have sometimes failed: they've made Lex a human being.

He's even friends with the teenage Clark Kent, played by Tom Welling. Their relationship and Lex's influence on Smallville factor in many episodes.

"I think Lex is a good judge of character," Rosenbaum says. "I think he sees a lot of things in Clark no one else sees. He sees Clark as a misunderstood guy, much like himself. He sees a lot of himself in Clark. Clark's got a lot of secrets, and Lex doesn't trust anybody. At least Clark has someone he can confide in, and Lex doesn't.

"Not only is he a good judge of character, but he means well. He has good intentions. But unfortunately, he's looked upon as being just another Luthor. He's trapped in the shadow of his father and he's trying to escape on a daily basis. It's very difficult."

In Superman comics lore, Clark and Lex eventually become enemies. And although there's been the occasional hint of friction and Lex has investigated the car crash in which Clark saves him, Rosenbaum says he hopes the Clark-Lex relationship continues to grow.

"I don't want Lex to get evil too quickly," he says. "If you get evil in the first season, then it's four years of evil. I want him to evolve. I want people to embrace the character and never really know what's going on with him.

"He means well, but there's that long journey that's ultimately there. Right now, it's better to embrace his character, that he is a human being and that he has feelings and that he means well."

Rosenbaum says he didn't really read Superman comics to prepare for the part, relying on an education from Gough and Millar.

"I know certain things that I should know," he says. "And they are trying to be true to the comics in a lot of ways, and try to be a little different as well, so I trust them in that regard.

"It's a juicy role. The character has the most depth. They really write a lot into it. I'm finding out things with every episode; there's something different. There's a relationship with Dr. Hamilton, my mother passed away - what's going on with her? The relationship with my father and my relationship with Clark, which is incredibly intriguing. There's so many facets with Lex Luthor that I never understood, and now I'm learning. Every week's a different week with him."

In addition to the long hours and working in Vancouver, Rosenbaum has to make a sacrifice his castmates don't: his hair.

"Everybody wants to talk about the hair," he says. "For me, now, I don't even think too much about it. I will miss not having to shave head. It's bad enough that I have to shave my face and my neck, because I'm kind of hairy. It's not a treat to wake up every morning and go in and shave your head. You get bumps, but you kind of get used to it. It is what it is, it's part of the job."

Rosenbaum says he would never use a skull cap for Luthor's permanently bald look.

"I tried one on, and I didn't like it," he says. "If there's one moment when it doesn't look real, it just ruins it. I wanted to keep the reality of the show."

Smallville isn't the only comic-book TV show with which Rosenbaum is involved. He does the voice of Flash in Cartoon Network's Justice League.

"Bruce Timm (producer) and Andrea Romano (voice director) gave me a chance because I was doing a lot of voice over work on Batman Beyond, Return of the Joker, Static (Shock) and The Zeta Project," Rosenbaum says. "They said, 'Hey, do you want to do the Flash?'

"I never really knew too much about the Flash, but I read it and gave my own take on it and again, you go with your instincts, and it's usually the right way. So I got that, and it's been the best of both worlds.

"Everybody's so great and we have such a good time. It's unfortunate because a lot of times I don't get with the other actors because we're filming. I have to fly down (to Los Angeles, where Justice League is recorded) and I have to do my lines by myself."

Rosenbaum says his favorite scene from the first season of Justice League came from "In Blackest Night," where Flash tries to defend Green Lantern in an intergalactic courtroom.

"I thought that was kind of funny with Habeas Corpus and Kappa Sigma Delta," Rosenbaum says. "I think he's a fun guy."

Suddenly Rosenbaum breaks into character.

"'So, Hawkgirl, where do you come from?'" he asks. "She's just looking at him, and he's like, 'Seriously, I really care.' C'mon, Flash. He's such a fun guy and he tries to make light of the situations. With all these horrible situations and everybody's so serious, you need that guy around. I'm that guy in real life."

Rosenbaum also does other voices, including Deadshot from "The Enemy Below" episode featuring Aquaman.

"That was fun," Rosenbaum says. "Sometimes Bruce will call me and say, 'Hey, when you come in can you do a Christopher Walken? You know, a really creepy Christopher Walken. We need one of those.' Sure.

"So then for Deadshot, he goes, 'Can you do your Kevin Spacey?' And you know how Kevin is, (breaking into character), 'So, anyway, here's the deal.' So I did it and sometimes it works. He gives me the freedom to try stuff."

Rosenbaum figures to have ample opportunity to try more stuff. Both Smallville and Justice League have been picked up for new seasons, and Rosenbaum is in Bringing Down the House.

"The animated series, a TV show, a feature movie -- life is good sometimes," he says.

Rob Allstetter, Deputy Sports Editor for The Detroit News, has been a comics journalist for the past decade, having written for numerous publications. He currently publishes The Comics Continuum. He can be reached at RobAlls@aol.com.