In September 2014, the organizers of the inaugural TomorrowWorld dance festival near Atlanta made a significant adjustment to the main stage lineup. Avicii, the superstar Swedish ambassador of electronic dance music, known as E.D.M., had canceled because of illness; his replacement was the lesser-known Norwegian producer-D.J. Kygo, born Kyrre Gorvell-Dahll, who’d picked up attention for a series of remixes he’d posted on his SoundCloud page and a performance at Tomorrowland, the event’s parent in Belgium, a couple of months earlier.

But he was largely unknown to this American crowd — and even riskier, he wasn’t playing hands-in-air anthems at a fist-pumping tempo of 126 beats per minute, or b.p.m., but slower, more languid tracks that typically fell closer to the 105 b.p.m. range. His music also features steel drums, trilling birdsong and pan flutes — touches that hew closer to New Age than the party-ready dubstep or electro-house that built the American E.D.M. audience this decade. Nevertheless, by the time he finished his set, the crowd was his.

“I remember I was a little nervous and skeptical if people were going to like the music, because it’s so different from the other people that played the main stage that day,” Kygo said. “But the response afterwards was great. There weren’t that many people listening to that style of music back then.”

Sixteen months later, Kygo, the 24-year-old producer and remixer, is signed to Ultra Records/RCA Records and has been commissioned to remix Coldplay. His tracks have been streamed a billion times on Spotify. Twenty-five Kygo songs — originals and remixes of other artists — are in rotation on Sirius XM’s Chill station. On Thursday night, he will headline at Barclays Center, playing live keyboards and triggering samples and presets on a lighted platform while being joined by a singer.