Early years (1985-1989)
Extreme was formed in Boston, Massachusetts, in 1985. Vocalist Gary Cherone was in a band with drummer Paul Geary, and guitarist Nuno Bettencourt was in a band with bassist Pat Badger. Following an altercation between the rival groups over communal dressing rooms Cherone, Geary, Bettencourt, and Badger decided to form a new band.

Cherone and Bettencourt began writing songs together and played numerous shows in the Boston area. The band gradually developed a strong local following, and was named "Outstanding Hard Rock/Heavy Metal Act" at the Boston Music Awards in 1986 and 1987.

The band had accumulated approximately 55 songs by the time A&R director Bryan Huttenhower signed them to A&M Records in 1988. The band then recorded their self-titled debut which was issued in 1989. The first single was "Kid Ego," a song that Cherone would later admit made him cringe. The final track on the album, "Play With Me," was used as the "mall chase" song in Bill & Ted's Excellent Adventure.

Popular success (1990-1993)
Album cover of Extreme II: Pornograffiti (1990), one of the band's most successful albums to date.

Moderate sales of Extreme's first record were sufficient to support a second release. Michael Wagener, who had previously worked with Dokken and White Lion, was engaged to produce Extreme II: Pornograffiti (1990).

The record, which showcased Bettencourt's extraordinary guitar-playing prowess, was an ambitious and complex mixture of funk, pop and Glam metal sounds. It revolved around a loose concept, following the path of young boy Francis as he wandered through a decadent, degraded and corrupt society. "Decadence Dance" and "Get the Funk Out" were released as singles. "Get The Funk Out" reached number 19 in the UK charts in June 1991. Neither single was successful in the United States, however, and the album had fallen off the charts when A&M sent the third single to a number of radio stations in Arizona.

The acoustic ballad "More Than Words" entered the Hot 100 on March 23, 1991, at Number 81. It later became a huge smash, hitting Number 1 on Billboard's Hot 100 in the United States. The subsequent single, "Hole Hearted," another acoustic and sweetly-sung tune, was also successful, rising to Number 4 on the same popular music chart.

The band began recording of their third album in 1992. Their appearance at the Freddie Mercury Tribute Concert in April 1992 interrupted the recording sessions, but it gave the band considerable exposure beyond the heavy metal fraternity.

Album cover of III Sides to Every Story (1992), the band's last album recorded with the "classic" line-up. III Sides to Every Story, a complex, eclectic and ambitious concept album, was released on September 22, 1992. Sales were disappointing despite the record receiving critical acclaim from some quarters. The video for the first single, "Rest in Peace," was inspired by a film short by the National Film Board of Canada called Neighbours.The band was sued, but they quickly settled out of court, later releasing a new version of the film clip. The album contained noticeable Christian themes, presumably put there by Cherone, who noted in interviews being interested in evangelical preachers and thought.