What is a tall, charismatic rocker who’s accustomed to doing his own songs, and swimming in his own emotions, doing in a moody musical theater piece?

“That’s a question I asked myself when I first started working on the show,” said Chris Koza, the Twin Cities singer-songwriter, bandleader and now stage star of “Fly by Night,” opening Friday at the Jungle Theater in Minneapolis. “Is it something I can do? Will it pen me in or will it allow me to grow in new ways?”

Koza has released five albums as a solo act and five more with his band Rogue Valley, whose music was used for the climax of Ben Stiller’s 2013 film “The Secret Life of Walter Mitty.” Now, making his professional theater debut at age 37, he’s subsuming his own ego to play a fictional character — albeit one not far removed from his younger self.

In “Fly by Night,” set during New York City’s famous 1965 blackout, he plays an aspiring songwriter, Harold McClam, who works as a sandwich maker and is caught between two sisters. One of the women is a traditionalist. The other is fearless and risk-taking.

“He’s dealing with the loss of a loved one” and finding his way through music, Koza said last week during a pre-rehearsal interview. As he spoke about Harold’s grief and dreams, it’s clear that he has a special affinity for the character’s struggles, even though he has to deliver it in a different manner from when he’s performing in concert.

“When you’re a musician [onstage], you want to stay in the pocket a little bit,” said Koza. “With this, you have to serve the character and the story. And Harold’s not staying in the pocket.”

Koza will have to cover up the tattoos that climb up both of his arms — the right arm has a desert-themed sequence of cactuses capped off by a great horned owl, and the left has the phases of an emerging cicada. His tats say something about life blooming in unexpected places, and little creatures that have a short moment to sing at the top of their lungs.

A youthful passion

Koza is rekindling a youthful passion that began in his hometown of Portland, Ore., where he performed in high school musicals, and that he nurtured at St. Olaf College in Northfield, where he did one-act plays while studying philosophy and studio art.

“I always loved the aspect of working together,” he said. “It’s like being a band that way.”

But how did this show come about? That question is best answered by Jungle artistic director Sarah Rasmussen, who graduated from St. Olaf the same year as Koza (2001) and is directing this 2014 musical by Will Connolly, Michael Mitnick and Kim Rosenstock.

“When we started thinking about doing this show, we thought: ‘It would be cool to have a real musical prodigy in it instead of an actor who kind of plays guitar,’ ” she recalled. Rasmussen sought the counsel of John Munson, the Twin Cities rocker who’s played with the bands Semisonic and Trip Shakespeare and more recently the New Standards.

“I told John my dream, which was to have a real musician with a Minneapolis sound, and he started telling me about this sincere, smart, soulful, sometimes silly guy,” Rasmussen said. “As he was using all the adjectives, I said, ‘You’re describing the kinds of shows I like.’ ”

The musical has given Rasmussen and Koza a chance to reconnect. “I saw some of his gigs in college, but I hadn’t kept up with Chris,” she said.

Will he pen his own musical?

Munson, who’s playing bass in the band for “Fly by Night,” said that what makes Koza a good fit for theater in general, and this role in particular, is that “he’s a great singer, first of all. He’s incredibly charismatic but selfless. And he’s game for anything, which means that he brings a really cool energy to a project.”

That’s good news for the cast, which includes Jim Lichtscheidl, fresh off his successful engagement in London with Mark Rylance in “Nice Fish,” and versatile performer Joy Dolo.

Munson has recorded with Koza and regularly enlists him for the New Standards’ holiday shows. That outfit is led by Suburbs frontman Chan Poling, who is something of a role model for both Koza and Munson. Both “Fly by Nighters” have ideas about musical theater, and Poling is something of a Twin Cities version of Elton John, having successfully crossed over with several musicals. His “Glensheen” is coming back for a third time at the History Theatre July 6-30.

“I’m not competing with Chan because he’s written his own works and I’m doing somebody else’s,” said Koza. “But this is a way to get my foot back in the door for something I love. Who knows where it will lead?”