The national tour of “American Idiot,” the hit Broadway musical penned by Green Day’s Billie Joe Armstrong, opens tonight at the Smith Center for the Performing Arts for the final eight shows of its 42-city tour.

The musical, inspired by Green Day’s acclaimed 2004 album of the same name, tackles heavy social and political themes centering on life in a post-9/11 world. At its center is Johnny, a disgruntled suburban youth who moves to the big city in search of something greater, portrayed by 21-year-old Alex Nee. Below, Nee discusses his relationship with his character, the challenges of performing and lessons from life on the road:

Though you took time off to perform in the show, you’ll be graduating from Northwestern University in a few weeks. How has the show influenced the perspective that you have now as a young person going out into the world?

Oh, interesting. Well, I’ll say for one thing I swear a lot more than I used to, which is a sort of superficial thing. Because the vocabulary of the show and the music is so aggressive, that has sort of crept its way into my vernacular. But other than that, I think the content of the show has allowed me to explore the darker sides of myself, which I think has been healthy and human. It’s not a happy show through and through; it goes through a lot of dark skies. And doing that has allowed me to ... move past those things, so I think generally I’m happier as a person.

Because you’re so close in age to Johnny, how did you make the character your own? What parts of yourself did you bring into that role?

I think a lot of my connection with the character comes from the age that I’m at. I think a lot of the problems that he’s going through are sort of common to people trying to figure out what it means to go from being a young person (or) teenager to taking on more of the responsibilities of an adult, and how that can be scary and exciting and in a transition period. Beyond that, there’s the fact that this is my first job out of school and I’m going out on tour, there’s a lot of unknowns, and very exciting unknowns, and I feel like that’s how Johnny starts out the show. He’s going off to the big city with his friends and thinks he’s going to make a big difference and change things and find his place, and so he’s very hopeful at that point. And then I think the letdown comes from his ultimate failure. I connected with that, I’ve had those moments I’ve had in my life where I’ve felt really alone, so I use that a bit. Though I’ve had a pretty good life, I’ve never reached that depth of despair that he approaches, so a lot of that was listening to the music and letting that and the lyrics go into my body and inform the emotions that way.

It’s a very physically demanding show — you’re on your feet singing and dancing intensely for 90 minutes. I even heard that you trained by learning to sing on a treadmill. How do you maintain that level of endurance when you’re traveling all the time?

It’s hard. We just had a break a couple of weeks ago because they were shipping our set across the country, and actually coming back to the show after a week of not doing it reminded me just how difficult it is. Even taking a week off from that constant athleticism brought me back down to where in rehearsals, I could barely make it through the show without feeling like I was going to pass out. But we have gyms in our hotels, so we often work out during the day. I’m usually every other day because I can’t get sore at the gym and then not do the show, as well, so I have to balance it. But the show itself is such a workout. We’re already getting eight times a week with that. It’s more cardio than I’ve ever done in my life. I’ve always been an active person, but this is a new level for me.

What music does the cast like to listen to when you’re on the road? Do you avoid listening to Green Day at all costs?

Ha! I was going to say, not Green Day. I love the band, I really do. And surprisingly, I’m not sick of the music of the show yet. But I can’t listen to it outside of (the show). Because the show’s so intense and pretty heavy in its sound — it’s punk and hard rock, which I love — on the road I listen to a lot more folk, bluegrass, blues, R&B. Recently I’ve been really jamming on the Lone Bellow; they’re this great folk-rock band out of Brooklyn. Matt Corby, Bon Iver, Mumford and Sons, that kind of stuff.

Because of the show’s social and political undertones, who are the audiences you see at your performances? Is it generally the same crowd or does it vary according to what part of the country you’re in?

It definitely seems to vary. We’ve got a nice spread of people because a lot of these theaters were a part of a subscription series, so there are subscribers who are kind of automatically going to our shows even if they wouldn’t have necessarily chosen to see it. Which I love, because it is a very specific show. It’s a bit heavy-handed in its political identity, so it’s nice for people who maybe wouldn’t necessarily agree with those politics to just be exposed to it. And if they’re open-minded, I think oftentimes they come out surprised at how much they liked it. But we also see a ton of Green Day fans, a ton of young people. In California so far, it’s been pretty crazy audiences, which has been nice.

What kind of feedback have you gotten from audience members after shows?

I think my favorite feedback to get is when people say they’ve never heard Green Day before or aren’t a Green Day fan but that they really connected with the characters and love the story as well as the music. We get a lot of people that connect to one of three boys, for different reasons. We get a lot of veterans connecting with Tunny’s character and his story. We’ve gotten a lot of letters from veterans and soldiers saying how much that means to them. I’ve had addicts come up to me and tell me how inspirational Johnny was to them and my portrayal of it. How they appreciated how I treated him, as a character, with respect, and how much that meant to them, respecting what they were struggling and going through. So that was pretty touching.

“American Idiot” opens at 7:30 p.m. Tuesday night at Reynolds Hall at the Smith Center for the Performing Arts, with eight performances running through June 16. Tickets start at $24. For more information and to purchase tickets, visit the Smith Center website.

Follow Andrea Domanick on Twitter at @AndreaDomanick and fan her on Facebook at Facebook.com/AndreaDomanick.