[6] The track was made available digitally simultaneously with the album on July 14, 2020, through Def Jam, Virgin and Big Hit.

[7] "On" was written by RM, August Rigo, Melanie Fontana, Michel Schulz, Suga, J-Hope, Antonina Armato, Krysta Youngs, Julia Ross, and its producer Pdogg.

[8][9][10] Lyrically, the song talks about how their success changed their lives, the sacrifices that they have made, and having the strength to continue their career despite "the unknown future.

[13] Writing for Time, Raisa Bruner noted that "On is already massive, kicking off with gospel-influenced organ, featuring propulsive percussion and a snare drum sing-along and tearing things up with an uplifting refrain" but Sia's presence "speaks to their ambitions to be taken seriously as a chart-topping pop act, regardless of language".

[15] The day after the song release, a Commentary Film was released showing the work UCLA Herb Alpert School of Music's Bruin Marching Band directors and team members had in the production of some of the songs on the album, and the essence of BTS' message.

[19] In South Korea, "On" debuted at number eleven on the eighth issue of the Gaon Digital Chart, for the period February 16–22, with less than two days of tracking.

[25] In the United States, "On" debuted at number four on the Billboard Hot 100, becoming the highest-charting song by a Korean group in the country, with over 86,000 digital downloads sold in its release week.

[35] The video contains references to various films and television shows, including The Maze Runner, Bird Box, The Handmaid's Tale, The Lion King, Game of Thrones, Narnia, and Dolittle.

[38] In the video, RM is shown standing before a ruined boat surrounded by various animals; Jin rescues an injured dove—which he later revives—from a war-torn battlefield; Suga stands in a middle of a cult; J-Hope is inside a forest filled with broken trees as Jungkook's dying body lies behind him; Jimin is near a boy with a drum; V takes a blindfold off of a little girl; and Jungkook is seen running from a prison wearing thorny handcuffs.