Lloyd Webber studied at Magdalen College, Oxford, and at the Royal College of Music. While a student, he began collaborating with Timothy Rice on dramatic productions, with Rice writing the lyrics to Lloyd Webber's music. Their first notable venture was Joseph and the Amazing Technicolor Dreamcoat (1968), a pop oratorio for children that earned worldwide popularity in a later full-length version. It was followed by the rock opera Jesus Christ Superstar (1971), an extremely popular though controversial work that blended classical forms with rock music to tell the story of Jesus' life. This show was one of the longest-running musicals in British theatrical history. Lloyd Webber's last major collaboration with Rice was on Evita (1978), a musical about Eva Perón, the wife of the Argentine dictator Juan Perón.

In his next major musical, Cats (1981), Lloyd Webber set to music verses from a children's book by T.S. Eliot. The London production of Cats became the longest-running musical in the history of British theatre, and in 1997 the Broadway production of the play eclipsed the record set by A Chorus Line to become the longest-running show ever on Broadway; on September 10, 2000, Cats closed after 7,485 performances. With lyricists Charles Hart and Richard Stilgoe, Lloyd Webber then composed a hugely popular musical version of The Phantom of the Opera (1986). It opened on Broadway on January 26, 1988, and in 2006 it surpassed Cats to become the longest-running Broadway show. His other musicals included Song and Dance (1982), Starlight Express (1984), and Aspects of Love (1989). He was knighted in 1992, and in 1997 he was created a life peer.

Lloyd Webber's best musicals were flashy spectacles that featured vivid melodies and forceful and dramatic staging. He was able to blend such disparate genres as rock and roll, English music-hall song, and operatic forms into music that had a wide popular appeal.