Tool guitarist Adam Jones has stated in an interview that the song is about a friend of the band whose artistic expression only comes out when he is under the influence. "A lot of people give him shit for that," Jones explains. "If you become addicted and a junkie, well, that's your fault."

"Sober" is one of the earliest songs composed by Maynard James Keenan, with roots dating back to a 1987 live performance (released as Peace Day with his first band, Children of the Anachronistic Dynasty) in which the song was called "Burn About Out". The song contains some lyrics from the first verse of "Sober", with the same basic melody, although the melody is considerably faster and has an instrumental chorus.

The song was recorded by MJK with Tool for the first time in mid-1991 on a demo tape titled 72826.

A video for "Sober" was made in 1993. It debuted in May of that same year and was directed by Fred Stuhr. It was filmed using stop-motion animation, with the characters' models designed by Adam Jones. It was the first of Tool's videos to be made in stop motion, the earlier promo video for "Hush" being live action. Whereas all four band members could be seen at all times during the previous clip, naked and without instruments, "Sober" shows only brief flashes of them, clothed and playing. A live-action clay figure is shown twitching and vibrating violently.

The video's protagonist is a small, humanoid being, who lives and sleeps in an abandoned mansion, in a rusty room sparsely decorated with a table, a chair, and a bed with no mattress and a curtain as a blanket. He happens to stumble upon a wooden box, which he opens near the beginning. Its contents are kept hidden for the majority of the video's duration, but it seems whatever it is has had adverse mind altering effects – there are repeated shots of the humanoid levitating in his chair, and his head and arm vibrating wildly. While experiencing these effects, the figure ventures through his living quarters and its many corridors.

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Wikipedia