Matthew McConaughey Invision/Associated Press

Matthew McConaughey is well into the second phase of his life on screen. In the last few years he went from a romantic-comedy hunk to a heralded dramatic lead of films such as "Mud" and "Dallas Buyers Club," playing unlikely AIDS activist (and victim) Ron Woodroof. The actor is getting a little weary of the notion that the career pivot was premeditated. "I know it would fit the narrative better if I told you I had a coming-to-God moment," he says.

In the last two years, actor Matthew McConaughy has transformed from an affable if innocuous romantic lead to one of the most sought-after dramatic actors in Hollywood. John Jurgensen discusses why 2014 may be a very good year for the actor. Photo: Getty Images.

Mr. McConaughey seems poised to build on his run in 2014, coming off a brief but potent turn as a cocaine-boosted trader in "The Wolf of Wall Street." The 44-year-old Texas native will anchor director Christopher Nolan's next film, "Interstellar," a tale of space and time travel scheduled for release next November.

HBO's "True Detective," premiering Jan. 12, marks Mr. McConaughey's first leading role in a TV series. He plays detective Rust Cohle, a nihilistic investigator who refers to humans as "biological puppets" and obsesses over homicide cases to keep his own dark proclivities at bay. Woody Harrelson stars as his seemingly squared-away partner. Over eight episodes, the story cuts between different time periods. In separate interviews with police in 2012, the former partners recount their investigation of a ritual murder in 1995 and its impact on them. "True Detective" was created by novelist Nic Pizzolatto as a so-called anthology series, meaning that any future seasons would feature a different cast, setting and story line. Below, edited excerpts from an interview with Mr. McConaughey.

Earlier Video

In the film "Dallas Buyers Club," Matthew McConaughey portrays a Texas cowboy who, in the 1980s, took on the medical establishment in his fight to survive AIDS. WSJ's Jason Bellini sat down with Mr. McConaughey and co-stars Jennifer Garner and Jared Leto.

Have you always been a Matthew?

Always. In kindergarten, I had a friend who said, "Hey Matt, you want to play on the monkey bars?" I said "Yeah," and ran off. And then I felt this hand on my shoulder pull me back and kind of slam me to the ground. It was my mother, who was my kindergarten teacher. "What's your name?" "Matthew." "That's right. Don't you ever answer to Matt again. I named you Matthew from the Bible for a reason."

Cohle, your character in "True Detective," is a grim guy, compared with the many upbeat, life-affirming characters you've played and, from what I've read, the kind of person you are.

I am an affirmative guy. I like to compare before I contrast. I like to find the common denominator. And I happen to believe in God. But Rust Cohle's like, "No. It's all a fallacy. It's something we've made up to give us a reason for being here." He's not a cynic, because everything he says has a huge kernel of truth to it. I've never played a character who is more honest.

Matthew McConaughey, Woody Harrelson in 'True Detective.' HBO

You're the rare actor whose characters often seem to represent some kind of philosophy or creed. Why is that?

I'm looking for the principles of the man. Look at the first role I ever did: Wooderson [a post-high school adult among teens in the 1993 movie "Dazed and Confused"]. One of his first lines was: "That's what I like about these high-school girls. I get older but they stay the same age." That line is not an attitude. It's not a bumper sticker for Wooderson. He honestly believes that. He may be smarmy and a has-been to everyone else, but in his mind, he's got it all figured out.

I've been trying to pin down what makes your "True Detective" character look so strange. His face is gaunt and it looks longer than yours does in real life.

Some of that's makeup, but I only gained four pounds after "Dallas Buyers Club" [he shed nearly 50 pounds for the role], which I finished a couple months before "True Detective." Hopefully what you're seeing is a guy who's boiling underneath. Having a case is Cohle's lifeline, what keeps him together. I had to keep him very subdued. Usually a movie is a 120-page script. This was intimidating, because it was a much longer rhythm: A 450-page script with a lot of crosscutting of different times. In a film, you usually have 40 pages before an event sends your character in another direction. This was 180, 200 pages, until Cohle goes off the rails. So it was weeks of working, telling myself, "Hold the line. Trust it. If I do it right, it will create tension." It was a real exercise in patience to not play his other colors too early.

What do you notice when you look in the mirror about the way your face is changing as you get older?

I don't put a period on the end of segments in my life. I'm more of a comma guy. Whether we know it or not, on our death bed, it's all going to be commas. It gives me excitement and hope for where I'm going. I've had people in a lot of these interviews talking about the work I've done in the last few years. They try to form a narrative of "then and now." As if I said "Ta da! I'm going to change my career and I'm not going to do any more of those rom-coms." Well, what have you got against rom-coms, man! I might do one again. It's a whole different game to have to be that buoyant. In fact, it can be more difficult.

It probably has to do with the audience's history with you. It's like the surprise of discovering that the regular guy down the street is actually a gifted woodworker who makes beautiful furniture in his basement.

It's not like I take anything more seriously now. Hell, in certain ways, there are things I don't take as seriously. I'm choosing characters who allow me to express myself in more and different ways. I go back to that word "identity." I've tried to look at the parallels in the characters I've been doing. I've been able to define their obsessions. And let's be frank, a romantic comedy or an action comedy is not about character-driven obsessed performances. Rom-coms are about human interaction and verbal ping pong. The stakes are never that high. Some dramas raise the ceiling and lower the basement on the amount of expression you can give. And they're a little closer to real life, which is a lot of times just more R-rated.

Does it bother you that so much of the attention on "Dallas Buyers Club" focused on your dramatic weight loss?

Do I understand why that was on the front page of Google before the film came out? Sure. But if you sit through the first scene in the film [his character getting intimate with two women in a bull stall at a rodeo], you're past that. You're thinking, "Who is this guy?" Honestly, the weight loss has made it easier for me to explain the character work I got to do for the role. For the months leading up to it, I put myself in a sort of hermetic lifestyle and surrounded myself with everything Ron Woodroof. I would sit with his transcripts and go through the scripts. I was inside. I wasn't going out to restaurants. He spent every waking hour trying to figure out how he could survive. He was a guy with a 7th-grade education who was becoming a scientist, an expert, on HIV. So I said, "Do everything you can, McConaughey, to become an expert."

On the scale between lightness and dark, where would you put your "Interstellar" character?

[Whistles a tune for a few seconds] Oh, well, I'd say he lives in a place that leans more toward the light, but he is heading into the deepest, darkest places man has never gone.

Your whistling reminds me of your scene in "Wolf of Wall Street," which ends with you humming and grunting and thumping your chest.

The last part of that take, I don't know if we spoke much English at all. We were like monkeys talking. It was all musical and beats and non-sequitur sounds and meanings. I love music, and I think that's where we, on a rhythmic level, really communicated.

Write to John Jurgensen at