Actor Lucas Hedges had his first film role at age 10, appearing as an extra in his father Peter Hedges' film “Dan in Real Life.” “I had a line, but it was cut,” he said. He's come a long way since then. Nearly 20, Hedges has a pivotal (and critically acclaimed) role in “Manchester by the Sea,” a drama written and directed by Kenneth Lonergan, due in theaters Friday.

He plays Patrick, a teenager whose mother is out of the picture and whose father has just died. Patrick is left in the care of his unwilling, and troubled, Uncle Lee (played by Casey Affleck). The character ranges from fighter to lover to goofball to grieving kid, and the film and all its performances have been collecting praise since premiering at the Sundance Film Festival.

Hedges, a student at the University of North Carolina School of the Arts, has taken his sophomore year off to work on two more films and an off-Broadway play. As he discussed his experience on “Manchester,” he made it clear he'd be happy to work for Lonergan again anytime. The following is an edited transcript.

Q: What was the most challenging aspect of portraying Patrick?

A: The danger was that I would turn him into a caricature of himself. He's very tough, he works on a boat, he's got a Boston accent. It would have been very easy for me to fall into a spoofy kind of performance because I'm really not like him at all on the surface.

Q: How did you avert that?

A: I created memories for myself as Patrick, in which I had been in physical altercations as a kid and came out victorious. And when I did that, it changed my physical chemistry; I walked into a room differently. It's crazy the influence our minds have on our physicality and emotional states. So it was very important to make the justification of his toughness literally real for me.

Q: Was there a line or a scene that helped you find your way?

A: My character has kind of a nervous breakdown, and without that scene I don't know if I would have been able to connect with the character on any level at all, because he's not really a part of this reality without it, given the circumstances of his life. If a character is not well-rounded, he's not really a character at all or a genuine depiction of a human being, because the light can't exist without the dark, and Patrick's playfulness can't exist without his profound sadness and longing for love.

Q: How did Kenneth Lonergan work with you?

A: There is zero improvisation in his movie. Every single detail is the way it is for a specific reason. But at the same time, Kenny likes to be surprised. He's very interested in the mystery of human nature; there's no way that anyone can understand how someone would react at any given moment to anything of any scale. That's very liberating as an actor because there's nothing more crippling than going into a scene believing you have to have a certain response. Opening yourself up to everything is really the only way you can find any truth.

Lisa Rosen is a freelancer.