In less than a decade, Michael Peña , a 36-year-old Chicago-born actor of Mexican parentage, has proved himself to be one of US cinema’s most nuanced and persuasive character actors. In 2004, he appeared in a brace of Best Picture winners scripted by Paul Haggis: Clint Eastwood’s Million Dollar Baby, in which Peña had a small role as an amateur boxer, and Crash (directed by Haggis), which gave him a meatier part as a young father caught up  in the film’s network of racial tensions. Since then, he has been impressive in a dizzying range of material, from manic comedy (Observe and Report, 30 Minutes or Less, Tower Heist) to contemplative drama (Robert Redford’s Lions for Lambs, Oliver Stone’s World Trade Center), from action movies (Battle: Los Angeles, Shooter) to the occasional indefinable curiosity (Werner Herzog’s My Son, My Son, What Have Ye Done?).
What he has rarely had until now is a lead role; character actors without a fixed persona don’t always find it easy to make the crossover. But End of Watch , a thriller from the writer-director David Ayer (Training Day), corrects that, putting Peña on an equal footing with his co-star, Jake Gyllenhaal. The actors play LAPD officers who stumble onto one grisly case after another, but the pleasure of the film comes less from the increasingly hysterical revelations than the bonhomie between these brothers in arms—Gyllenhaal like a human cocktail stick, Peña cuddly as a teddy bear. I met Peña during his visit last month to the London Film Festival.
Did it take long to work up the camaraderie with your co-star?
It was strange. Once I got together with this guy [gestures to image of Gyllenhaal on the End of Watch poster behind him], it took us the longest time to get anything going. There was something stopping us. We had to ride around a lot and spend a lotta time together before we began to feel we could trust each other. And maybe there’s a grain of that in the film, but there’s a lot of affection too. He has the confidence to hang back and give me a scene. He said to me on the set: "I want to do whatever I can to help you be awesome." Now, not a lot of actors in his position would watch out for you like that. Most would want the whole show to themselves.
You bring a lot of breezy comedy to what is a very serious film. How did you see your responsibilities to the movie?
I’m just an actor. If it’s drama, I add as much humour as the part will stand. And if it’s a comedy, add as much drama as you can, so it balances out; you don’t wanna be too serious. I went to church a lot, and the best pastors always told a lotta jokes, a lot of anecdotes. A good comic explores the imagination but it’s always got to have those notes of truth running through it. When I think of the actors I admire, they can seemingly do it all - comedy, drama, action, everything. I can’t do it all yet. I’d love to do a romantic comedy: that’d be awesome, a whole other realm.
Have you been offered any?
I’ve been offered parts in them, but never the whole thing. I love When Harry Met Sally. That’s an awesome arc. And it has such real humour. I haven’t read a lot of scripts like that. They’re usually more tongue-in-cheek.
Has it been a struggle to reach the stage where you’re getting lead roles?
Man, the whole thing’s been a struggle. My first ten years in Hollywood were really tough. I’d be coaching friends who came to me for acting advice, and then they’d make it before I did. I’d still be helping them while they were on movie sets and I had four lines on a TV show.
Was that a race issue?
Well, it’s a … It coincides with the population, I guess. The major population at that time in America was, I’m sure, Caucasian, and I understand that’s what people relate to. But times are changing. And that has afforded me the luck to star in a movie alongside Jake Gyllenhaal, and to not be the sidekick. Obama’s got a lot to do with that change. It’s a fantastic time for me right now. My kid looks Mexican even though his mother is white, and I hope life’s a lot easier for him.
Did you realise at the time why it was so hard for you to get a break?
Pretty much, yeah. I was only offered auditions that were written specifically for a Latin male. That’s not so much the case now. For instance, Tower Heist was written for someone else; I came in to audition and they gave me the part . Observe and Report was written for some white dude trying to be black. But I went in and said, "What about me?" And they were like, "What?" The way I went in there with this crazy character  ]
really convinced them. The Lucky Ones, Shooter—these were written as white. It’s come a long way. I don’t even know where it started. It could have been when Diego Luna and Gael Garcia Bernal did Y Tu Mamá También or when Alejandro González Iñárritu [who directed Peña in Babel] started breaking through. I dunno. But it changed.
How did you cling on when work was hard to come by?
I didn’t wanna do anything else. I would have done this even if I was just doing theatre and I had to work at a bank in the day. I love creating characters. At first I was doing it for the money, to make more than I did working at the Board of Trade in Chicago, but then I got to love it. To be honest with you, I did think I was gonna have success. But I didn’t know if it was gonna be as third banana on some TV show. I never dreamed of this. I mean, I’m in London! People are asking for autographs. That’s funny to me. What you gonna do with an autograph?
Didn’t you experience anything similar after the success of Crash?
Not like this. The joy of Crash was that it was all about the work. It was my first real part. Before that, it was a line here and there, maybe a scene. Crash was five scenes, a beautiful arc, a little vignette of my own. It really meant something. I feel the same about End of Watch. Even though it’s a cop movie, it’s about relationships, brotherhood.
Were you at the Oscars when Crash won?
I wasn’t invited. I wasn’t even included in the SAG [Screen Actors’ Guild] award for Best Ensemble that we won. Some rule. I wasn’t eligible because… I don’t know. My name wasn’t on it anyway. But it was my first real gig so … S’all good. Shit happens, you know? It’s funny how that was an important year for both of us. Jake was the Brokeback Mountain guy, I was the Crash guy. Both our lives changed that year.
I read that your next role is as the civil rights activist César Chávez.
First I did Gangster Squad , a big shoot-‘em-up movie, very much an ensemble [the cast includes Ryan Gosling, Nick Nolte, Sean Penn, Emma Stone]. But Chávez  I really dug. My big concern is how to show this man’s life without being preachy and pushing the audience. I did a whole transformation. I have to deliver these long, long speeches in his very nasal voice. I gained 30lbs. Rehearsed constantly, over and over again. It’s really my first lead, the first time I’m carrying a film. I waited a long time for something like this.
"End of Watch" is released 23 November; "Gangster Squad" on 11 January 2013.