Björn Kristian Ulvaeus was born in Gothenburg on April 25, 1945. When he was six years old the family moved to the small town of Västervik, and this is where Björn grew up.
In the mid-Fifties Björn fell in love with rock'n'roll and skiffle. By the early Sixties he was a member of a folk group called the West Bay Singers. In 1963 they entered a talent contest arranged by Swedish radio. This led to discovery by songwriter and publisher Stig Anderson and his partner, Bengt Bernhag. Stig and Bengt had recently started a record company called Polar Music. The band acquired a new name, the Hootenanny Singers, and quickly became one of Sweden's most popular groups of the Sixties.
In 1966, Björn had a chance meeting with Benny Andersson, himself a member of Swedens number one pop group, The Hep Stars. They hit it off and wrote their first song together, 'Isn't It Easy To Say'.Björn recorded a couple of solo singles in the late Sixties, at which point he also started concentrating more on his collaboration with Benny Andersson. In 1970 the pair started releasing records as a duo and also staged a cabaret show together with their fiancées, Agnetha Fältskog and Anni-Frid Lyngstad. On July 6, 1971, Björn and Agnetha got married.
From 1972 and a decade onwards Björn was occupied by his work with ABBA. In 1983 Björn and Benny started writing the musical Chess with lyricist Tim Rice. A concept album was released in the autumn of 1984, and in May 1986 the musical opened in London's West End. In 1988 Chess received its Broadway première. A reworked version of the musical opened in Stockholm, Sweden in 2002.By 1990, Björn and Benny had decided to write a new musical. This time they wanted to write exclusively in Swedish, and they chose the Emigrants novel series by author Vilhelm Moberg as basis for their work. The musical Kristina från Duvemåla (Kristina From Duvemåla) opened in October 1995. The show ran for three and a half years at various theatres in the Swedish cities of Malmö, Gothenburg and Stockholm.
Recently, Björn has involved himself heavily in the staging of MAMMA MIA!, a musical based on ABBA songs. The show opened in London, England in April 1999 and has since then been staged virtually everywhere, even being turned into a movie which opened in July 2008.