John Michael "Ozzy" Osbourne (born 3 December 1948) is an English singer-songwriter, whose career has now spanned four decades. Osbourne rose to prominence as lead vocalist of pioneering British heavy metal band Black Sabbath, and eventually achieved a multi-platinum solo career which revolutionized the heavy metal genre. As a result he is known as the "Godfather of Heavy Metal", and, because of some of his material, the "Prince of Darkness". In the early 2000s, his career as a celebrity hit a new zenith when he became a star in his own reality show, The Osbournes, alongside wife/manager Sharon and two of their three children, Kelly and Jack. In August 2008, Osbourne stated in USA Today that he intends to retire from his music career after two more albums.

Osbourne was born in Aston, Birmingham, England. His father Jack worked shifts as a toolmaker at GEC and his mother Lillian for the car components firm Lucas, to support him and his five siblings. Osbourne reportedly suffered from learning difficulties (claiming to be dyslexic) making life at Prince Albert Road Junior School and Birchfield Road Secondary Modern School in Perry Barr difficult for him. However, he did like music and took part in school plays. He also became a great fan of The Beatles from the age of 14 when he heard their first hit single. He left school at 15 and was then employed as a construction site labourer, trainee plumber, apprentice toolmaker, car factory worker and slaughterhouse worker. He also spent a few weeks in Winson Green Prison, when he was unable to pay a fine after being found guilty of burglary of a clothes shop.

Osbourne would later form a band with former Birchfield Road School classmate Tony Iommi after he auditioned for a lead singer. During this time, psychedelic rock was enormously popular. To distinguish themselves from the norm, Iommi and his partners decided to play a heavy blues-inspired style of music laced with gloomy lyrics. Names for the band included Polka Tulk and Earth. They later learned of another travelling band of the same name. One day during rehearsals, the band noticed people queueing up outside a cinema where a horror film was being shown, and bassist Geezer Butler observed how curious it is that people like to be frightened. The film these fellows were waiting to see was the Mario Bava-directed Black Sabbath. After reading an occult book that Osbourne had let Butler borrow, Butler had a dream of a dark figure at the end of his bed. Afterwards, Butler wrote the lyrics to "Black Sabbath", one of their first songs in a darker vein. It was the prototype of the songs that became their main style later in their career.