Daniel Ek, the 28-year-old co-founder and public face of Spotify, the European digital music service, paced around the company’s loftlike Manhattan office on Tuesday afternoon, clutching two mobile phones that buzzed constantly.

After nearly two years of stop-start negotiations with record labels, Spotify was preparing to finally open in the United States. With less than 48 hours before its planned start, however, the company still had not completed its final major label deal, with the Warner Music Group.

Yet Mr. Ek said he was confident that there would be no delay, and that Americans would soon be able to experience what has made Spotify the world’s most celebrated new digital music service. He was right. By Wednesday afternoon, Spotify’s deal with Warner was signed, and on Thursday, as scheduled, it will become available in the United States.

“We’ve made it easier to listen, and we’ve made it easier for people to share,” Mr. Ek said. “Hence, people tend to get more into the experience, and they tend to find new music and build larger collections that they want to take with them. And therefore, they also pay more for music.”