Morissette began studying piano at age six and composing at seven; she wrote her first songs at nine. By age 10 she was acting in You Can't Do That on Television, a series on the children's television network Nickelodeon. She used her earnings from that show to cut her first single. At age 14 Morissette signed a song-publishing deal that led to two dance-pop albums, Alanis (1991), which sold 100,000 copies and earned her Canada's Juno Award for most promising female vocalist of the year, and Now Is the Time (1992), which sold more than 50,000 copies.

Escaping from the pressures of her then-fading teen career, Morissette left home after high school to create a more satisfying and authentic style. She eventually settled in Los Angeles, where she met Glen Ballard, a veteran songwriter-producer. Together the two wrote and recorded Jagged Little Pill (1995) in record speed and at negligible cost. The album featured the explosive single "You Oughta Know," a searing fantasy of revenge against an unfaithful lover. She signed with Madonna's label, Maverick, and Jagged Little Pill, which Morissette considered to be her real debut, sold more than 14 million copies and remained atop the international billboard charts throughout 1995 and 1996. In 1996 Morissette won Grammy Awards (Grammy Award) for album of the year, best rock album, best rock song (songwriter), and best female rock performance.

Morissette's follow-up, Supposed Former Infatuation Junkie, which she coproduced, appeared in 1998. Featuring Eastern-influenced music, the album was noted for its ballads and catchy pop songs. In 1999 her single "Uninvited" for the film City of Angels (1998) won two Grammy Awards, including best rock song. Morissette returned to the recording studio (without producer Ballard) for Under Rug Swept (2002), a confessional album that received mixed reviews. So-Called Chaos (2004) also failed to re-create the critical and commercial success Morissette had enjoyed in the mid-1990s. In 2005, 10 years after Jagged Little Pill's release, Morissette took it on tour as an acoustic act and released an album version, Jagged Little Pill Acoustic (2005).

In addition to working on her music, Morissette continued to act occasionally. In 1993 she made her film debut with an uncredited role in Anything for Love (1993). She later portrayed God in Kevin Smith's Dogma (1998). Her television work included appearances on the HBO series Sex and the City (2000) and Curb Your Enthusiasm (2002) and on Nip/Tuck (2006).