The song premiered live on 27 March 1996 at the Fillmore in San Francisco. Radiohead performed the song several times in 1996 during their stint as Alanis Morisette's opening act, which were chronicled in numerous bootleg recordings. The song was recorded for the band's 1997 album OK Computer but rejected for inclusion. Guitarist Ed O'Brien claimed the band was considering rerecording the song for their next album, but it this didn't surface as the band went into a new musical direction for 2000's Kid A. O'Brien denied it was being considered for 2007's In Rainbows. The song finally surfaced in 2017 for the 20th-anniversary re-release of OK Computer on a second disc titled "OKNOTOK."
Robin Hilton of NPR interpreted the music video as a reference to the "grueling" schedule and sense of isolation Yorke experienced while on tour for OK Computer.
The song was premiered on BBC Radio 6 on 2 June by host Steve Lamacq who said that Radiohead were "especially pleased to find [the song] in the vaults, because they thought it'd been lost over the years." The same day, Radiohead released "I Promise" as a download for those who had pre-ordered OKNOTOK, along with a music video on their website.
On tour in June 2017, Radiohead performed "I Promise" for the first time in 21 years. Yorke told the crowd: "What a bunch of nutters we were, and probably still are. One of the things - one of the crazy things we did - was not release this song, because we didn't think it was good enough."
In interviews years before the song's release, O'Brien likened "I Promise" to Roy Orbison, while Yorke likened it to Joy Division. The song features strummed acoustic guitar, marching band-like drums, and Mellotron "washes of orchestral tones." The lyrics see Yorke "listing off vows like a shopping list," with themes common to OK Computer including loneliness, alienation, paranoia and heartache. NME described the song as "Radiohead at their most direct" before moving into electronic music with later albums.[9]