During the recording of Achtung Baby, conflict arose between the band members over the direction of U2's sound and the quality of their material. Tensions almost prompted the band to break up, until guitarist The Edge composed a chord progression that inspired the group to improvise the song, which was written as a ballad. The group worked on the mix for "One" throughout the remainder of the album's sessions. The lyrics, written by lead singer Bono, describe struggles to maintain relationships with others, but they have been interpreted in other ways.
"One" was released as a benefit single, with proceeds going towards AIDS research. The song reached number seven on the UK Singles Chart and number ten on the Billboard Hot 100, and it topped the US Billboard Album Rock Tracks and Modern Rock Tracks charts. In promotion of the song, the band had several music videos filmed, although they were not pleased until the third video was created.
The song has since been acclaimed as one of the greatest songs of all-time, and it is consistently featured in listener and critic polls. The song has been played by U2 at every one of their tour concerts since the song's live debut in 1992, and it has appeared in many of the band's concert films. In a live setting, "One" is often used by the band to promote human rights or social justice causes, and the song lends its namesake to Bono's charitable organization, the ONE Campaign.
Looking for inspiration on the eve of German reunification, U2 began the recording sessions for Achtung Baby in Berlin's Hansa Studios in late 1990. However, the mood was bleak, and conflict arose within the band over their musical direction and the quality of their material. While bassist Adam Clayton and drummer Larry Mullen Jr. preferred a sound similar to U2's previous work, vocalist Bono and guitarist The Edge were inspired by alternative rock and European electronic dance music of the time and were advocating a change. The band also had difficulty in developing demos and ideas into completed songs. Bono and The Edge believed the lack of progress was the fault of the band, while Clayton and Mullen Jr. believed the problem was the song ideas. Mullen said he "thought this might be the end" of the band.