Despite all the attention being given to “In the Bedroom,” its lead actor Nick Stahl is in danger of being forgotten. The film, which opens in Boston on Tuesday, already has won the L.A. Film Critics prize as Best Picture, the N.Y. Film Critics’ Best First Film award and, for leading lady Sissy Spacek, Best Actress honors from both groups.

Somehow, even with an actor’s healthy ego, the 21-year-old Stahl doesn’t mind. “It’s exciting to me to challenge myself with different kinds of roles and Sissy is just amazing to work with. You meet her and she’s incredibly grounded and unaffected. “She lives on a farm in Virginia with her family and there’s an innocence to her that’s amazing, and a workmanship. Just very inspiring I’d say, so normal and fun.

“I was really just trying to hold my own with these great actors, it was such an accomplished group. It wasn’t competition, I was just trying to survive.”

Stahl plays Frank, a promising collegiate destined to be an architect who finds a summer romance in his Maine fishing village with the slightly older Natalie (Marisa Tomei).

Ultimately “In the Bedroom” is not a warm romance but a wrenching study of a family – Spacek and British actor Tom Wilkinson as upright small town Maine parents – coming undone when a beloved son is murdered by his girlfriend’s out-of-control ex.

For Stahl, “In the Bedroom” is his second buzzed-about flick of the year, following Larry Clark’s “Bully,” in which he played a murdered sexual predator. “`Bedroom’ was pretty simple,” Stahl said. “Once I read it, that was it. Every movie is different in one way or another, but this was one of the better experiences I’ve had, I would say.

“Frank’s a great role for me, I was just fortunate. I saw him as old for his age, I don’t think he’s more than 21. He’s mature for his age and kind of wise.”

When it comes to acting, Stahl, too, has been mature for his age. “I’d been doing children’s plays since I was about 4,” he said. “At 10, I got a role in `Medea’ with a professional theater group as her son, so I started off with death at a young age.”

That was when he was growing up in Dallas, where he soon had an agent and did TV movies. At age 12, Mel Gibson changed Stahl’s life.

That’s when Stahl was cast to star in “The Man Without a Face,” directed by and co-starring Gibson. “He’s a good guy to be around,” Stahl said of Gibson. “He had his hands full with directing. He had a great sense of humor and fun, so it made it easy for me.

“I was just in awe, my first movie and such a big thing to start on. It kind of blew me away.”

Stahl continued to work, appearing in “The Thin Red Line” and “Eye of God,” but only now are his roles finally changing. “I look pretty young for my age, I have this baby face,” he said. “`In the Bedroom’ is the first role really where I’ve played an adult.”