For Swedish siblings Johanna and Klara Söderberg, singing is in the blood. "We love the Louvin Brothers and the Carter Family," gushes Klara, 17, a wide-eyed beauty who's two years younger than her sister. "There's something very special about families singing music that's passed down through the generations." Ever since they can remember, the fresh-faced duo behind First Aid Kit have sung together while their musician father recorded them at the family home outside Stockholm. Last year, keyboardist Johanna and guitarist Klara uploaded a YouTube clip of themselves covering Fleet Foxes' pastoral, harmony-laden "Tiger Mountain Peasant Song" in the woods near their house. Wearing flannel shirts and no makeup, they sang with heartbreaking simplicity under the trees and sky. "We just loved the song," Klara insists. "We had no idea that anyone was going to see it."
Since then, the sisters' raw performance has racked up more than a million hits on YouTube. And Karin Dreijer Andersson of Swedish electronic duo the Knife -- who released First Aid Kit's first EP, Drunken Trees, on her Rabid label -- has lent them a little indie-rock cred. "I think Karin recognized herself in us," explains Johanna, "because we're also young Swedish girls trying to make it outside of Sweden. She takes care of us like she's our mother."
In May, First Aid Kit made their U.S. debut with The Big Black and the Blue (Wichita), an elegantly spare folk album filled with crisp acoustic guitars and earnest, bonfire-ready sing-alongs. "We want the music to feel like it was made just for the joy of making music," insists Johanna.
That kind of talk probably makes Mr. Söderberg want to lock up his daughters before boyfriends and A&R reps wreck things. But for now, having recently completed their first headlining U.S. tour, First Aid Kit is sticking with this whole bliss thing. "At South by Southwest [last March], a guy on a bicycle rode up and shouted, 'Fleet Foxes!' and rode away," laughs Klara. "Then he came back and said, 'I'm so sorry, I meant, First Aid Kit!' But people are coming up to us on the street. That never happened in Sweden!" Joy indeed.WATCH: First Aid Kit covers Fleet Foxes's "Tiger Mountain Peasant Song" (South by Southwest)