Sam Hunt partied in celebration of “Leave the Night On” in Nashville on Monday (Jan. 26) alongside co-writers Shane McAnally and Josh Osborne. His boundary-pushing debut single went No. 1 on the Billboard airplay chart and sold more than 1 million copies.

While the singer says he tries not to focus too heavily on chart position or sales, he’s more than thrilled by the track’s popularity.

“I just watched the audience through the summer after the song came out,” he told CMT Hot 20 Countdown. “Slowly but surely, the show went from the first couple of rows singing it to three, four, five, six. And then by the end of the summer, the whole crowd was singing the song back. I kinda figured that it must be doing well on the radio, reaching a lot of people, and folks must be digging it.”

“Leave the Night On” was the lead single from Hunt’s first album, Montevallo. When the project was released, he wasn’t sure how well the song would do. After singing a song so many times, he says it’s hard to tell what it will sound like to fresh ears.

“I was still excited about it, but I think I lost a little bit of objectivity,” he said. “So when we put it out, I was kind of like, ‘I hope people dig this.’ But right off the bat when it started playing on the radio and people started reacting to it, I gained back that confidence, and it’s done phenomenal things for us. It’s changed our lives.”

The popularity of Hunt’s style of music isn’t just changing his own life and career. It’s becoming part of the changing face of today’s country sound as a whole.

“I think the genre has evolved the way that I have evolved as an artist or as a songwriter,” he said. “If you listen to the songs that I wrote when I first moved to town and you listen to the songs that are on this record, there’s a big difference, but as time goes on you want to progress as a writer and as an artist. … I think historically the genre has always evolved. Nobody wants to hear the same thing over and over and over -- I think -- and I’ve just stepped into that and hopefully found a little niche.”

Hunt will kick off his Lipstick Graffiti tour Thursday night (Jan. 29) in West Hollywood, California.

For more from CMT Hot 20 Countdown’s interview -- including details on Hunt’s ACM nomination -- tune in to an all-new episode this Saturday and Sunday (Jan. 31-Feb. 1) at 9 a.m. ET/PT.