British musician, who gained a loyal following as vocalist for the heavy metal group Black Sabbath before embarking on a successful solo career.

Raised in a working-class family, Osbourne dropped out of school at age 15 and held several low-paying jobs. He also engaged in petty crime and at 17 was imprisoned for two months for burglary. After his release, he sang in a number of local rock groups, eventually forming the rock band Earth with guitarist Tony Iommi. To avoid confusion with another band of the same name, the group changed its name to Black Sabbath—after an old Boris Karloff (Karloff, Boris) movie. The group developed a grinding, ominous sound, based on the blues but intensely amplified, and drew attention with its tendency to reference the occult in its lyrics. In February 1970 Black Sabbath released its eponymous first album and quickly developed a following in both Britain and the United States.

The band released albums each year through the mid-1970s, except 1974. After the tour for Never Say Die (1978), Osbourne left the band. A period of despair and drug abuse led to Osbourne's divorce from his first wife, Thelma Mayfair. He then met and married Sharon Arden, who encouraged him to start a career as a solo artist. His first effort, achieved with the primary help of guitarist Randy Rhoads, was Blizzard of Ozz (1980). A multiplatinum success, it was followed by the equally popular Diary of a Madman (1981), which sold more than five million copies. A defining moment in Osbourne's career came on the tour for the album, when, thinking that someone in the audience had thrown him a rubber toy, Osbourne bit off the head of a live bat.

Osbourne found his first solo Top 40 hit with "Mama, I'm Coming Home" from the album No More Tears (1991), and in 1993 he won a Grammy Award for best metal performance for the song "I Don't Want to Change the World." Despite announcing his retirement in 1992, he continued recording through the decade. Ozzfest, an annual summer music festival featuring heavy metal acts organized by Osbourne and his wife, began in 1996 and toured throughout the United States and, in some years, parts of Europe. By the end of the 1990s, Osbourne had reunited the original members of Black Sabbath for a new album and tour, and in 1999 the band won a Grammy for best metal performance for the song "Iron Man."