Emile Hirsch was inspired by SpongeBob SquarePants for new role — playing a bloody killer

Emile Hirsch went looking in a pineapple under the sea to draw inspiration for his latest role. The actor plays court stenographer Walden Dean in the new thriller “Walden,” who seeks revenge on criminals that bypass prosecution.

Hirsch, 38, initially had “no idea how to play” the role when he originally got the part — that is, until he found his voice.

“There was a straight kind of version, a little more simplified version of the character. And I knew it was the safe way to do it. There was something about it that didn’t land,” he exclusively told the Post. “It’s not satisfying something for me. There’s something missing from it. And the sense of humor of the character — really, I didn’t really buy it.”

That is, until he looked to the 2005 drama “Capote.”

“I was really inspired by a series of sources,” he said. “And it was Philip Seymour Hoffman in ‘Capote.’ An example of a really unique voice. And I loved him in the movie. I mean, the movie’s got a dramatic shell. And I loved Sean Penn’s exuberance in ‘Milk’ and just the way there’s a certain fun to it. I loved that. … And I’m in ‘Milk,’ so I had a front row seat on doing that. So I had a very unique perspective on it. And there was also — he lives in this suburban community. There’s something almost that reminds him of like Ned Flanders in ‘The Simpsons.’”

Hirsch developed the peculiar character of Walden with the help of a Nickelodeon series, too.

“I had just finished watching six seasons of ‘SpongeBob SquarePants’ with my friends. And there was just something so funny about SpongeBob and Squidward and Mr. Krabs,” he went on. “In certain moments SpongeBob’s unrelenting positivity, which is kind of like Flanders and kind of like ‘Milk’ and not so much the Capote element. But those were kind of loose inspirations and not even necessarily inspirations in a sense of like, ‘Oh, I want to sound like that.’ It was more like, ‘Look at these bold choices these actors have done and more drawings and actors have done at times and how they really work.’”

“And so I sort of was playing around with the radio dials. Listening close, turning to different frequencies. And it was kind of like all of a sudden, I hit just the right frequency. And Walden was just there,” he explained. “It felt like a eureka moment because suddenly, suddenly the character made sense to me. The sense of humor that he had, his pathos, his his kind of turning into this vigilante who does these pretty, you know. Heinous things in a way, even though you’re kind of grimly satisfied that he’s taken out the trash.”

The “Into the Wild” actor appears alongside good friend Shane West (Detective Bill Kane), Kelli Garner, Tania Raymonde, David Keith, Steve Coulter, Seth Michaels, Sunny Mabrey and Luke Davis.

Hirsch also had writer-director Mick Davis in his corner, who often sided with Walden’s bloody, lawbreaking acts.

“He was biggest cheerleader for Walden. He’d be like, ‘Oh, they all deserve it. They’re getting away with heinous crimes,’” Hirsch recalled to the Post.

“Any doubt [I had] he would pat me on the back and reassure me to a ridiculous degree where I’m like, ‘Well, I guess you’re right.’”

The “Girl Next Door” star didn’t take his work home with him either.

“It’s definitely not the most moral thing he does, to put it mildly. But yeah, that was kind of how that was. It was sort of like that Robert Frost poem, taking the path a little less traveled by. I sort of felt like I’d taken the safe way on other films,” he said. “I don’t want to say it didn’t bother me because then I sound like I have issues just saying that, right. I slept like a baby. It wasn’t like that.”

Hirsch was able to detach from his character, in part, because of the company he kept while filming.

“I had my son and my nephew with me on the shoot. My son was like 8 years old. And we were hanging out and I finished work and I’d go play baseball at the field with my son. Or I’d be taking them to Six Flags on my weekends off,” he said.

Hirsch welcomed his son, Valor, with an ex in Florida in October 2013.

“The amount of roller coasters I had to ride while I was shooting ‘Walden’ was absurd because every day there would be no one at Six Flags and my son and his cousin would just [go on] the scariest roller coasters. I had to ride, like, an insane amount of roller coasters, and I was terrified and screaming. But yeah, no, I actually had a really fun time making [the movie].”

“Walden” is now available on demand and on digital.