When he plays Lego Batman, Will Arnett doesn’t wear a cowl like Christian Bale or toss a Batarang a la Ben Affleck. And there’s really no reason to pour himself into a skintight suit when working with the guy playing the Joker.

Still, Arnett takes the animated superhero he voices seriously, unleashing equal helpings of machismo and vulnerability in “The Lego Batman Movie,” which turns the Bat-signal spotlight on the supporting hero from 2014’s “The Lego Movie.” The actor doesn’t see his blockheaded, self-obsessed Gotham City vigilante as different from any other role.

“I’ve always approached him from an emotional standpoint of like, ‘What’s he going through at this particular time? Even when he’s just fighting criminals, what’s his motivation?’ That sounds like actor-speak but I actually mean it in a very human way,” says Arnett, 46.

“This story is just as important to Lego Batman as some character in some dramatic live-action film. He doesn’t know he’s in an animated film.”

With the Joker (voiced by Zach Galifianakis) and other baddies threatening his hometown, Batman has to stop adoring his masculinity long enough to figure out he needs the help of his sidekick Robin (Michael Cera), faithful butler Alfred (Ralph Fiennes) and new cop pal Barbara Gordon (Rosario Dawson).

“Will takes him on a journey of self-exploration,” producer Dan Lin says. “Batman basically has a midlife crisis in this movie and has to find out who he’s really about.”

What makes Arnett’s Batman special is the actor’s “unbelievable” ability to create lovable jerks, says “Lego Batman” director Chris McKay. “There’s 1 percent of 1 percent of 1 percent of people who can be that guy where he’s saying the things we shouldn’t say or do but we still love him.”

Arnett found some deep-seated issues with his cartoon do-gooder. For one, Batman almost never takes off his cowl: “That’s his protection mechanism, literally and figuratively.” And after a day of fighting crime, Batman comes home alone and talks to a picture of his parents, murdered when he was a child, about how he saved the world. “That’s why he does what he does, and there’s something really sad about that,” Arnett says.

The actor relished being able to be physical while recording scenes with Galafianakis, facing off with each other like a real Batman vs. Joker battle rather than just being static in a studio. The only time Arnett was hampered was last August after knee surgery. “I jerry-rigged a chair and bags of ice [in order] to record and sit,” he recalls. “It was awkward and painful.”

But Arnett was a workhorse in every session, McKay says. “I just had to wind him up and let him go until his voice gave out.”

Arnett cherry-picked from previous movie Batmen for his heroic vocals — with Bale’s deep growls being a strong influence — that remain constant whether kicking butt or dealing with mundane life problems like getting the TV to work.

“It’s Batman in a therapist chair — it’s Tony Soprano in a lot of ways,” says Arnett, adding that he loves being many kids’ first taste of the Dark Knight. “My own sons [Archie, 8, and Abel, 6] haven’t seen the film versions because they’re too scary and too violent, but what’s great is that they can watch the one that their dad does.”

Brian Truitt, USA TODAY