Lyngstad was born in Bjørkåsen, Ballangen, Norway, to a Norwegian mother and a German father. Her parents separated when she was young, and she was raised by her mother in Torshälla, Sweden. She began singing at a young age and performed in various local bands before joining ABBA in 1972.
As a member of ABBA, Lyngstad sang lead and backing vocals on many of the group's biggest hits, including "Dancing Queen", "Mamma Mia", and "The Winner Takes It All". She also wrote or co-wrote several ABBA songs, including "Fernando" and "I Have A Dream".
ABBA broke up in 1982, and Lyngstad went on to have a successful solo career. She released several solo albums, including "Something's Going On" (1982) and "Shine" (1984). She also collaborated with other artists, including Phil Collins and Elton John.
In 1992, Lyngstad married Prince Heinrich Ruzzo Reuss of Plauen, a German nobleman. They lived together in Switzerland until his death in 1999. Lyngstad currently lives in London, England.
Lyngstad has been active in environmental causes since the 1980s. She is a Goodwill Ambassador for the United Nations Environment Programme (UNEP) and has worked with various organizations to promote environmental protection. She is also a supporter of animal rights and has spoken out against animal cruelty.
In 2015, Lyngstad was inducted into the Rock and Roll Hall of Fame as a member of ABBA. She continues to perform occasionally and is still considered one of the most successful and influential singers in the world.