When he was 15, some friends asked Eric Johnson to be the singer in their band.

He was terrified — but not about singing.

“Was I just supposed to dance [onstage] or what?” he said.

Rather than a failing attempt to shake his hips, he picked up a guitar and forced himself to play. In the first day, he learned two chords.

“They weren’t enough chords to actually play any songs, any that I knew of at least, so I just wrote a song,” he said. “But it was probably terrible.”

Since that moment, the singer/songwriter hasn’t stopped. But now, rather than playing with high-school buddies, he is associated with such acts as the Shins, and he is considered by many to be one of the best modern songwriters in the folk world.

His primary band, Fruit Bats, will play at 9 p.m. Friday at the Mill, 120 E. Burlington St., with Blue Giant. Admission is $10.

Together since 1999, Fruit Bats has released four albums, the most recent being 2009’s The Ruminant Band. The latter’s single “The Primitive Man” was selected as Starbucks’ iTunes single of the week this past December, and the group also had music featured in the recent movie Youth in Revolt.

Before The Ruminant Band, Johnson, although he wrote all the songs and arrangements, allowed and encouraged more group collaboration with recording.

“I’d approached previous records with a conceptual or solo approach, in a lot of ways, and when I put a band together for the road, I wasn’t always able to translate it live,” he said on the phone while unloading for a show in New York City. “We recorded a lot of the stuff in a live context in the studios.”

With that approach, Fruit Bats’ sound is often compared with the music of the ’60s and ’70s. KRUI director Nathan Gould believes the group’s live show is one of its strongest qualities.

“The live show is so high-energy and fun,” he said. “And in terms of recordings, there are a lot of bands doing what it is doing, but Fruit Bats stands out as much more polished.”

However, with that common comparison with classic rock, Johnson is afraid the depth of his work is sometimes lost.

“I think people get caught on the fact that it’s sort of upbeat and happy-sounding music,” he said. “Sometimes, people think it’s this weightless thing, and it’s really not. I’m still trying to write about the big picture and my viewings and the world.”

In that big picture, he leaves his listeners wondering. With the exception of a few songs, most of Fruit Bats’ music is not driven by narrative.

“I like to leave things kind of open-ended, so then people can apply it to their lives in an easier way, rather than it being this specific story,” he said.

However, simply because the lyrics can carry numerous meanings doesn’t mean Johnson writes in a careless or less meaningful way. He knows what he wants to write and hopes listeners take whatever they want from his songs.

“I’ve always wanted to write about the realities of the world in an honest way but doing it with an undercurrent of hope,” he said. “But it’s whatever. It could be a story of a failed romance or just a bunch of bull that comes out of my head.”