Actor T.C. Matherne says he's really just living in the moment — and who wouldn't?

In the past 18 months, the Baton Rouge native who just turned 30 has gone from shooting a Popeyes commercial to working alongside Hollywood heavyweight Sean Penn. In between, he's guest-starred on "NCIS: New Orleans," and will be seen next year on HBO's "True Detective" and on the big screen in "Godzilla: King of the Monsters."

For now, you can catch Matherne in the new Hulu streaming series "The First," in which he plays Jason, the assistant to space program director Laz Ingram (Natascha McElhone). Academy Award winner Penn, 58, stars as astronaut Tom Hagerty in the fictional story centering on efforts to send the first crewed mission to Mars.

Matherne appears in seven of the season's eight episodes.

"It started out, I think, as a smaller part than it ended up being," Matherne says. "I think I was only written into maybe the first two episodes. So I went in for a week, and then the next week they called me in again, and then they called me again, and called me again, and I ended up working for over three months.

"I don't know what happened on their side of the writing room … but they kept writing stuff for me, which was really nice."

Matherne describes Jason as a bit different from himself.

"I'm kind of a get-my-hands-dirty kind of a guy, and Jason's more a professional, wears the nice suits and he does his job really well," Matherne says.

The series was shot in several locations around New Orleans, including Lakefront Airport. Unlike other projects in which the city subs for somewhere else, "The First" keeps New Orleans as New Orleans, Matherne says.

"It features New Orleans in a really beautiful way, I think."

Such as the opening scene in which Tom (Penn) is taking his daily run on the levee. His apartment across the street looks over the Mississippi.

"I was fortunate enough to shoot a lot of stuff with Sean. And he's great. He's such a character on his own," Matherne says. "He's a very polarizing person. People either love him or they hate him because of the stories they've heard. But literally every moment I spent with him he was just a complete gentleman. He'd find little places that served pralines or something and he'd bring them for the cast and crew. I was a huge fan before, but I'm even more so now after having worked with him."

Unlike Penn, acting wasn't Matherne's first calling. After graduating from LSU with a psychology degree, a trip to Chicago to visit his uncle ended up pushing Matherne in a new direction.

"He got me a ticket to an improv theater, and I saw improv comedy for the very first time, and I fell in love with it. And I came home, packed my bags and moved up to Chicago," he says. "I was up there for five years studying and performing at Second City, iO (Theater), all the major places up there and I really enjoyed it."

Moving back to Louisiana 18 months ago, Matherne acquired an agent and started acting from there.

"I never really had any intention of doing scripted work, but it turns out my improv training has given me a leg up on a lot of people because it's given me the ability to be very adaptable," he says. "When a director comes to me with a note, or a different way of doing something, I can just jump right into it. The hardest part for me about acting is memorizing the lines."

And that psychology degree?

"I think it helps me have empathy for my characters, to put myself in that place."

Follow Judy Bergeron on Twitter, @judybergeronbr.