Paul Dano

LOS ANGELES — With a shuffling gait and wearing jeans, sneakers and a blue plaid shirt that matches his eyes, Brian Wilson is at the center of a Hollywood whirlwind.

This day, he’s been rushing to screenings, giving interviews and posing for photos at a Los Angeles hotel as his new biopic prepares to hit theaters.

“It’s a trip,” Wilson says.

Ten years in the making, “Love & Mercy” takes an unflinching look at Wilson’s powerful creative energy and debilitating mental illness, demystifying the man who created the sunny sounds of the Beach Boys before descending into a dark world of personal demons.

“The first time I watched it, it was like a real test for my emotions,” Wilson said in his typical clipped diction. “It portrays me so well that I felt like I was being pushed into the movie.”

That meant re-experiencing some of his highest highs and lowest lows. “Love & Mercy” focuses on two formative periods in the musician’s life, separated by 20 years.

Paul Dano plays the younger Wilson at perhaps the peak of his creative genius, when he stayed behind from the Beach Boys’ world tour to create his opus “Pet Sounds.”

Feeling confined by surf music and inspired by the Beatles’ 1965 album “Rubber Soul,” Wilson wanted to expand the Beach Boys’ sound and give form to the melodies and harmonies he imagined.

He employed an orchestra, climbed inside a piano to plink its strings with a bobby pin, and incorporated everyday sounds like keys jangling or dogs barking into the songs.

Commercially disappointing at first, “Pet Sounds” is now considered one of the most influential compositions in popular music. But it was such a sonic departure that it caused a rift in the band, which exacerbated an emerging personal crisis for Wilson. He began showing signs of mental illness, hearing cacophonous voices and sounds in his head.

John Cusack plays Wilson in the 1980s, a broken man, heavily medicated and terribly insecure, under constant watch by his Svengali-like psychotherapist, Eugene Landy (Paul Giamatti). While shopping for a Cadillac, the troubled musician forms an instant connection with saleslady Melinda Ledbetter (Elizabeth Banks), who would go on to liberate him from Landy’s care and become Wilson’s second wife.

Director Bill Pohlad interweaves the two narratives, creating a portrait both painful and triumphant.