– You’ll never mistake Rainn Wilson for Mr. Popularity.

From the sarcastic, antagonic Private Gar in the Guthrie’s 1996 production of “Philadelphia, Here I Come!” to the power-hungry Dwight Schrute on NBC’s “The Office,” the actor has specialized in characters you wouldn’t want to sit next to on a plane.

“I have no interest in playing someone well-liked or balanced,” he said this week in a hotel bar, placing his trademark nerdy spectacles on a glass table. “Misfits. That’s what I love to play.”

Wilson continues his mean streak with “Backstrom,” a drama premiering Thursday on Fox. He plays the title role, a brilliant detective with horrendous social skills who appears to hate everyone, including himself.

So, “House” with a badge? Not exactly.

“The big difference is that House had coping mechanisms, where Backstrom is falling apart. He wears his heart on a sleeve in a way House never did,” said Wilson. “Plus, let’s face it, Hugh Laurie is a way better actor.”

His castmates have nothing but praise for the show’s star.

“Watching Rainn bring Backstrom to life was honestly one of the highlights of my acting career,” said Kristoffer Polaha, who plays a forensics expert on the series. “Watching him create the character was like witnessing a murder, because he was sort of saying: ‘Well, how would Dwight do it?’ and then go in a totally different direction.”

Fatter was better

Part of the transformation was physical. During the course of shooting, Wilson, who just turned 49 Tuesday, packed on 15 pounds and gave his razor a holiday.

“It’s a really dangerous thing when you play a character where the fatter you are the better it is for the character,” he said, waving off a waitress. “Your mind does all these gymnastics to justify stuff. ‘Oh, maybe I’ll have that extra doughnut, you know, or I’ll have the French fries with the sandwich instead of the salad.’ I just needed to be out of shape and weird looking.”

Wilson’s all-out devotion comes partly from his background working for Guthrie director Joe Dowling, who gave the actor prominent roles in “The Venetian Twins” and “The Importance of Being Earnest.” The two reunited in 2011 with a sold-out Q&A on the theater’s thrust stage.

“Joe always worked on us as actors to make as bold a choice as we possibly could, to really go for it,” he said. “You only get to play the role once, so why not dive in and bring all of yourself to the role as truthfully and as theatrically as possible? There’s a lot of choices I could have made to make Backstrom more likable, but I wasn’t interested in that. I wanted to see how far we could push the envelope.”

Wilson’s efforts were almost for naught. The pilot was originally shot for CBS almost two years ago. The network turned it down.

“The show eventually ended up where it needed to be,” Wilson said, referring to Fox. “CBS shows are very slick and the characters don’t have much personality. Here, the procedural comes second to the characters.”

Hart Hanson, who runs both this series and “Bones,” said Wilson was the show’s biggest cheerleader, even when its future appeared dim.

“Rainn never, ever lost hope and I had to pretend that I was optimistic, too,” Hanson said.

As the drama’s star, Wilson put in 13-hour days over five months of filming in Vancouver. He memorized seven or eight pages of dialogue a day, endured lots of outdoor shoots and put up with stunts and fake blood.

“It almost killed me,” he said.

The lead role also came with a new responsibility: setting the tone on the set. He had a perfect role model, though, in “Office” star Steve Carell.

“I have a newfound appreciation for what he had to do, because he worked a hell of a lot harder than any of us,” Wilson said. “He had lot a more pages of dialogue and most importantly, when you’re No. 1 on the call sheet, you’ve got to drive the scenes.”

A yen for the live stage

“Backstrom” is far from a guaranteed hit. Its competition includes water-cooler favorite “Scandal” and the final episodes of “Two and a Half Men.”

If the show is canceled, would Wilson be interested in taking over for Dowling, who will leave the Guthrie at the end of this season?

“Put my name in the hat,” he joked before seriously mulling the question. “I’d love to come back to doing theater, and running a theater would be fantastic. I’d love to be involved in all aspects. When you run a theater, you have to be kind of evangelical. You need to turn people on to the power and magic and majesty of theater and enlist the support of a huge community in order to do that.”

In other words, you have to be Mr. Popularity — and Wilson, the actor, isn’t ready to play that role just yet.