Aaron Olson grew up in Del Mar listening to his parents playing records of Paul Simon, Talking Heads and the Beatles, which inspired him to pursue a career in music.

His latest accomplishment was creating the musical score for “Nutcrackers,” a feature-length film starring Ben Stiller that debuted Sept. 5 at the Toronto International Film Festival.

In his first lead role in about six years, Stiller plays a real estate developer who leaves his city life in Chicago for rural Ohio to care for his four nephews, whose parents died suddenly in an accident. Working with a family services worker, played by Linda Cardellini, he tries to find a new home for the four children, who are also trained in ballet.

“It’s a little like ‘Bad News Bears’ but less naughty,” said Olson, who got the gig through a musician friend who had previously worked with director David Gordon Green.

Years before that, his foray into music started when he learned piano and guitar as a child. He said he remembers an uncle teaching him bass lines on electric guitar. As a student at San Francisco State, Olson tried to pursue a dual music and film major, but a program that combined those two fields didn’t exist so he majored in classical music.

Films such as the 1998 comedy “Rushmore” helped him see the possibilities for combining his musical abilities with film.

Olson said developing the score for “Nutcrackers” involved a lot of collaboration with the director, music supervisor and editor.

“We talk about what kind of music needs to underscore all these moments, and then I write down all these things and I start writing music to try to support the story and the visuals,” Olson said. “That goes through a lot of back and forth.”

He’ll receive instruction to make a particular moment on the screen “joyous” or “zippy,” and then use his musical expertise to craft the notes and progressions to create those feelings.

“It’s a mixture of musical intuition and music theory,” Olson said.

Olson recorded as much as he could himself at his home in Los Angeles, including the guitar, bass, harmonica, drums and piano that viewers will hear as they watch the film. Other musicians contributed with the chamber orchestra element that included clarinet, flute, violin and cello.

Olson also makes music with his band LA Takedown.

“I straddle a lot of styles personally,” he said.

Visit www.tiff.net/events/nutcrackers for more information.