It began as an eight-minute jam that young Canadian producer Bob Ezrin persuaded the band into tightening into a tight three-minute rocker.

The Alice Cooper band formed in the mid-1960s and adopted its name in 1968, presenting an origin story that it came from a 17th-century witch whose name they learned from a session with a ouija board.

[6] The group's first two albums, Pretties for You (1969) and Easy Action (1970), appeared on Frank Zappa's Straight Records label, and failed to find an audience.

The band relocated to Detroit and found itself in the midst of a music scene populated with the hard-driving rock of the MC5, the stage-diving Iggy Pop with the Stooges, and the theatricality of George Clinton's Parliament and Funkadelic.

The Alice Cooper band incorporated these influences into a tight hard-rock sound coupled with an outrageous, theatrical live show.

[8] While at the Strawberry Fields Festival in Canada in April 1970, band manager Shep Gordon contacted producer Jack Richardson, who sent nineteen-year-old Bob Ezrin in his place.

[11] The band resisted at first, but came to see things Ezrin's way, and ten to twelve hours a day of rehearsal resulted in a tight set of hard-rocking songs with little of the psychedelic freak-rock aesthetic of the first two albums.

[14] Ezrin found it a challenge to capture Cooper's raspy vocals with standard techniques; he settled on using a Shure SM57 microphone with high compression and judicious addition of treble and midrange equalization.

The performance also features some distorted lead guitar, vocalist Cooper on harmonica during the intro, and an organ that joins the band for the closing chord.

[14] Cooper's sings with raspy vocals of the existential anguish of being at the cusp of adulthood, decrying in each verse being "in the middle"—"of life" or "of doubt".

"[24] The band played "I'm Eighteen" live on the German television show Beat-Club in 1972. Cooper appeared on the floor in a Wonder Woman T-shirt gripping a whiskey bottle.

During an extended intro, Cooper declares "I ain't twenty-one", then "twenty-two" and on until "twenty-five" before the band delivers an aggressive, heavily distorted performance of the song.