Joel Sass wore a jacket in Park Square Theatre’s air-conditioned performance space.

The director hugged his arms to his chest as he watched the crew run a transition for the second time, looking satisfied.

David Lindsay-Abaire’s newest work requires Sass to be detail-oriented. Whether it’s a smooth, cinematic transition or the subtlety of set placement, the little stuff is crucial to making Park Square’s production of “Good People” flow.

“It’s very much in two different worlds. There’s the Southie, slummy world, and then, you know, there’s the pristine world of the doctor’s office and the house,” actor and University of Minnesota alumnus Sam Pearson said.

When Pearson says Southie, he’s referring to the blue-collar Boston neighborhood. “Good People” is a play about two different people from this place — one who got out, and one who did not.

The protagonist, Margie Walsh (Virginia Burke), is the latter. After being fired from her job by Pearson’s character, Stevie, Margie finds herself in a financial predicament.

Her ex-boyfriend, Mike, moved out of Southie a long time ago. Now he’s a physician and enjoys a comfy life in the suburb of Chestnut Hill. When Margie comes to his office to ask him for a job, “Good People” becomes a biting comedy about class and how much luck has to do with success.

“Isn’t that the great myth that we tell ourselves in America?” Sass said. “We’re all equal here, and everyone should be able to rise in a Horatio Alger way if they have ambition.”

Lindsay-Abaire’s writing reflects this idea and has been praised for its unrelenting charm and dedication to character. The Pulitzer-winning playwright’s work isn’t easy to perform, though.

“You’re juggling all this stuff. You’re talking about something, and then all-of-a-sudden you do a 180 and talk about something completely different, because that’s how our brains work,” Pearson said.

This style attracted the cast and crew to the play. The characters speak colloquially and the scenes are paced realistically.

Hope Cervantes, another University alumnus, said she’s thrilled to play Mike’s wife, Kate.

“I’m excited to be playing a character of color who’s very educated. I think it’s rare for playwrights to write these characters and for theaters to put them on the stage,” she said.

This production of “Good People” is all about challenging norms. Whether it’s through its unapologetic dissection of class structure or blurring of what it means to be a “good” person, Burke said this quality makes “Good People” powerful.

“It hits hard and it hits for a lot of people,” she said.

What: “Good People”

When: 7:30 p.m., Sept. 13-Oct. 6; 2 p.m. on Sundays

Where: Park Square Theatre, 20 W. 7th Place, St. Paul

Cost: $25-58