LOS ANGELES—Character actors don’t usually have a lot of control over the roles they play. If they want to work, they show up, do the audition, and hope it works out. Stanley Tucci has been lucky of late. Three years ago, he costarred with Meryl Streep in The Devil Wears Prada and she pushed for him to play her diplomat husband in this year’s Julie & Julia. Then director Peter Jackson decided he could play a serial killer named George Harvey in The Lovely Bones, which opens January 15. Tucci has already won Golden Globe, Critics’ Choice, and Screen Actors Guild nominations for the role, and he just might get his first Oscar nomination after 25 years of making movies.

In an L.A. hotel room, Tucci says that although he knew it was a great part, he was aware that, as a parent, he probably wouldn’t have seen the movie if he hadn’t been in it. The film stars Saoirse Ronan as a girl who dies at the hands of a neighbour but is stuck in a world between heaven and earth, observing her family’s grief.

“I would say without question that it was the most difficult thing I have ever done. I was reticent to take the part because I have kids, and I can’t really watch anything or read anything about kids being harmed. I don’t like to think about serial killers. There is so much information out there, and a lot of it is just gratuitous or almost pornographic.

“But this was a beautiful exploration of loss. Peter [Jackson] and [producer] Fran Walsh and I had several conversations before we started working together, and I felt very safe with them. I felt there was nothing here that was gratuitous and that we would be creating a real person. We felt that the more real he was and the more subtle he was, the more terrifying he would be. At the beginning of my research it was very hard to leave it, but eventually when I understood who he was, I could drop him at the end of the day.”

The most difficult scene was one in which he takes the friendly Mr. Harvey and turns him into a monster. Tucci says that he and Ronan faced the challenge together. “Saoirse and I talked before we shot it, when we were getting to know each other. You know that you have to behave a certain way in order to get what you need across in order to fulfill the needs of the screenplay, but after every take I would ask Saoirse if she was okay, because it made me uncomfortable. She would ask me if I was okay, and, as it turned out, she was the one who made us all more comfortable because she was so mature.

“When it was over, I breathed a sigh of relief. It’s your job to do that thing and then take off the mask and go home to your kids.”