TORONTO -- Michael Shannon never expected to be a Hollywood leading man when he first got into acting. And he certainly didn't imagine playing the lead villain in a big-budget summertime popcorn flick.

But that's where the respected actor finds himself now, after establishing his chops in the theatre world and then building an impressive collection of increasingly significant character roles and stealing scenes in his projects along the way.

"It's different now, for a long time when I did films I was supporting, a player, or cameo and now I've got a couple under my belt where, here I am, the title character, which is nothing I ever anticipated," says Shannon, star of "The Iceman," which is screening at the Toronto International Film Festival.

The tall, lanky Shannon doesn't have the typical Hollywood leading-man look. He's won his roles on the strength of his auditions and past work; not because he has the kind of bankable sex appeal that big-budget films are often built around.

"It's funny because when (director Ariel Vromen) first started trying to put this movie together, he told me -- he was very candid -- he said, 'I would love for you to play this part but I don't know if I can get the financing with you in the part,' because you know, we all know how that works," says Shannon.

And consider that for "The Iceman," Shannon's part didn't even call for a hunky, suave figure. He plays Richard Kuklinski, a real-life hitman who was convicted of carrying out 100 murders for New York crime organizations in the 1970s and 1980s. He was arrested and convicted in 1986, much to the shock of his wife and children, who had no idea about his secret life that supported them.

Shannon says it's a "big relief" that he now finds himself getting scripts for interesting leading man roles but he still didn't expect the call he received from Zack Snyder, director of "Watchmen" and "300." He and producer Christopher Nolan said they wanted Shannon to play the villain General Zod in the upcoming "Man of Steel" Superman flick.

"I was a jump for me, because that's such a huge responsibility in such a big film. I was suspicious of it originally and it did in fact take a while for me to finally get the job -- a lot of people had to sign off on it," Shannon says.

"It wasn't something I pursued necessarily, it kind of just surprised me. But once I finally got the job and started working on it I was very happy to be doing it.

"I'm sure excited for it to come out because not only will it be a blockbuster, but I think it's going to be a really great movie."

Asked by a reporter about hearing possible Oscar buzz for his role in "The Iceman" -- Shannon got a best supporting role Academy Award nomination in 2008 for "Revolutionary Road" -- he modestly brushed off the award season chatter.

"I honestly don't know what to do with that information, when people say, 'Oh you're in the running for this or that,"' he says.

"Unless you're, like, a real arrogant, kind of egocentric, narcissist-type person it's always awkward to talk about that stuff. I can't honestly say that I look at the film and think, 'Wow, I deserve an award for that, I've really gone above and beyond the call."'