The song was released on June 21, 2017, through Syco Music and Columbia Records, and is the lead single from VanderWaal's debut studio album, Just the Beginning.

VanderWaal introduced the song live at VidCon in June 2017, and she released a music video of "Moonlight" on her YouTube Vevo channel the following month.

[2] When she released the first single from the album, "Moonlight", she commented on the song's meaning: "'Moonlight' is about somebody you know very well changing unnaturally over time right in front of you and pushing you away, so you want to help bring them back to their original self.

[4] Cayla Bamberger of J-14 wrote: "The track delivers all that we love about VanderWaal: her raspy vocals, a heavy beat, her signature ukulele, and an acoustic sound.

[3][12][13] Among other broadcast performances of the song, VanderWaal sang it at the first live results show, in August 2017, of America's Got Talent, season 12.