(CNN) -- For five years, Michael Emerson was the villain who stole just about every scene on "Lost." (And he has the Emmy to prove it.)
He was such an important part of that landmark series that it only seemed to make sense that he ended up on the side of good, keeping watch on the island when it was all over.
Now Emerson is on the island of Manhattan, filming "Person of Interest," one of the top dramas on television.
On the CBS sci-fi procedural, Emerson plays Finch, a mysterious genius whose creation, the Machine, can predict crimes before they happen. This time, his character's motives are more pure.
Emerson spoke to CNN about settling into this new role, an accidental visit to the set of "Gossip Girl" and his old friend from "Lost," Terry O'Quinn.
CNN: Now that you have a year under your belt, is Finch still a mystery to you?
Emerson: He's still a bit mysterious to me. I play it every day and I hope I play it well. I don't have a very elaborate mental biography for him, I must say. I think he must evidently be a lot like me, because whatever my instincts are about the scenes tend to be the things that get used.
CNN: Would you describe him as a good guy at this point?
Emerson: I don't think his altruism is in doubt. If anything he has misgivings about the purity of his suicide mission for justice.
CNN: With so many productions going on in New York, I heard you had a run in with one of them.
Emerson: One day we were shooting downtown in the financial district. We just finished a scene and the company was breaking up to go to lunch. I don't know if I stood and gabbed with somebody on the curb. Next thing, I looked up and couldn't find anybody from our company, and I guess I zoned out when they drove me there in the van because I couldn't remember which direction I came from. I started walking and I got to another camp and it looked like ours. But it was another show. [Laughs] I'm sure they would have fed me. I think it was ["Gossip Girl"].
What if it were more surreal or absurd, where characters from "Person of Interest" walked into "Big Bang Theory" or something like that? That's a fun idea that has been completely unexplored.
CNN: Do you run into your old friend from "Lost," Terry O'Quinn, who is shooting (the now-canceled-but-still-in-production) "666 Park Avenue?"
Emerson: It's fun to have an old pal from the other island here on this island. He lives less than 20 blocks away from me. We get together every week or 10 days.
It is a bit [like old times]. It's just the setting is more urban and we're much better dressed. We both have really nice clothes in the shows we're doing now.
CNN: What did you two have in common on "Lost?"
Emerson: To start with, we had age. We were both the oldest guys on that show. We had many more things in common: small town Midwestern backgrounds, and we both moved to big cities to pursue the unlikely dream of being an actor. We both ended up accidentally on a big series. We had some of the same work habits. We had so many things in common. We had a bunch of the best scenes on the series. It was good, intense, dark work and yet we had good laughs doing it.
CNN: So you were a villain and now you're a hero.
Emerson: I'll stick with that. Villains generally are more fun, but they're hard to maintain. I guess anything is hard to maintain in TV land. I'm happy that my character on "Person of Interest" has enough ambiguity that it's still compelling in that villain way, except he's not. He does operate on the wrong side of the law so at least we have that.
CNN: Do you ever talk about projects you can do with your wife, Carrie Preston ("True Blood")?
Emerson: We sometimes talk about plays we'd like to do together. That shows how our minds work.
I shot a few scenes with her on "Person of Interest," which was a great pleasure. We'd never done TV work together.
CNN: What about a guest spot on "True Blood"?
Emerson: I'd be happy to do it, but I don't think it's ever going to happen. I can't go on there and play anything sinister because I've kind of done that. I guess I could play an innocent. I've said I'd be happy to play a humble human who gets torn apart by supernatural beings.
The characters I like on that show are the most ancient ones. I like Godric. I like thinking about how he looks like he's 19 but he's 2000 years old.
CNN: And what was it like voicing the Joker in the "Dark Knight Returns" DVD movie?
Emerson: If I knew how significant it was to play that role in that franchise, I think I would have been terrified when I took it. I must have been busy or distracted, because I went in there carefree. I had not seen these recent big screen "Batmans." That's probably a blessing. Later when I saw Heath Ledger, I thought "Oh, God. If I'd have seen this, I might not have done it." As it was, my only role model was Cesar Romero, and I thought, surely I can do as well as Cesar Romero.
CNN: Did you get to laugh?
Emerson: I did. It was a chance not to be repressed or contained. All the shows I do, it's all about keeping a lid on it or staying small. When you play the Joker, the sky's the limit. You can turn that thing up to 11.
I know it's a franchise where people have very high expectations and loyalties to whomever has played before, so I hope they'll accept me.