Born in Glasgow, Scotland, he became famous as the lead singer with the openly gay pop group of the time, Bronski Beat and later with the The Communards (with Richard Coles). Later he started a solo career.
Somerville was twenty-three when he formed Bronski Beat in 1984 as a collaboration with Steve Bronski and Larry Stenbachek. The three musicians met while they were working on a video by young gay men and lesbians entitled Famed Youth. It was during this project that Somerville realized that he could sing.
Bronski Beat's debut album Age of Consent (1984) included a pink triangle on the cover and listed the age of consent for gay sex in European countries on the inside sleeve as a means of calling attention to the disparity between British and Continental laws at that time.
Consisting of a series of songs dealing with various aspects of gay life, the album sold more than a million copies. In 1985 Bronski Beat teamed up with another gay singer, Marc Almond, to record a version of Donna Summer's "I Feel Love," which was also a hit.
After a series of disagreements over politics, Somerville left Bronski Beat in April 1985 and formed another group, The Communards, with another gay musician, Richard Coles.
Somerville worked with ACT UP, using his celebrity status to highlight the AIDS epidemic and the plight of people with HIV. As a result of his activities with ACT UP, he was arrested in 1990.