Born in Stockholm on 21st August 1957, grew up in Nybro in the province of Småland. Qualified as music teacher in 1980 before commencing the composition course at the Royal College of Music in Stockholm, where her teachers included Gunnar Bucht, Pär Lindgren and Brian Ferneyhough.

A characteristic feature which has often been mentioned in connection with Karin Rehnqvist’s music is the cross-fertilisation between art music and folk music. The folk music element is an integral part of her music and is not just used for effect or for nostalgic reasons. Nevertheless Karin Rehnqvist is unmistakably an art music composer, although her music does not easily fit into categories or “isms“ but retains its distinctive character, unaffected by art music issues. This means that discussions about modernism and postmodernism or the exclusive and the popular are without relevance where Karin Rehnqvist’s compositions are concerned.

A significant early work, Davids nimm (1983), was presented at Rostrum 85 and won immediate international acclaim, and as a result soon became widely performed. Karin Rehnqvist’s specific aims regarding timbre and performance techniques have meant that she has often worked in close contact with musicians. Her important collaboration with Lena Willemark and Susanne Rosenberg in fact commenced with Davids nimm.

An attractive feature of several of Rehnqvist’s works is her use of “kulning“. This archaic song technique produces a loud, high-pitched tone without vibrato which carries over a great distance and was used by herding girls to call the animals in the mountain grazing pastures. Examples of kulning can be heard in Puksånger–lockrop (Timpanum Songs – Herding Calls, 1989) which caused a considerable stir at the ISCM World Music Days in Stockholm in 1994, Rädda mig ur dyn (Rescue me from sinking in the mire, 1994) and Solsången (Sun Song, 1994).

Karin Rehnqvist often thinks in vocal terms and her music is characterised by a kind of motivic and rhythmic “breathing“. This also applies to her instrumental works, as for example Kast (Sudden Changes, 1986-87) and, as the title implies, Lamento – Rytmen av en röst (Lamento –Vibrations of a voice, 1993).

Between 1976 and 1991 Karin Rehnqvist was the leader of the choir Stans Kör. This resulted in a close relationship to vocal music and also roused her interest in different approaches to concert performances. This experience has coloured several works whose form has grown out of an overall performance concept, as for example Vishetens lov (In Praise of Wisdom, 1996) and Anrop–Inrop–Utrop (Cries and Calls, 1997).

1999 -2003 Karin Rehnqvist was composer in residence with Scottish Chamber Orchestra and Svenska Kammarorkestern in co-operation. For them she composed the much performed Arktis Arktis!, inspired from a polar expedition in the summer of 1999. Also composed recent years are "Sötskolan" (The Sweet School) - opera thriller for children from 10 years old (1999), and the radio phonic play Passionsspel (Passion Play) - like four sports disciplines (1988 - 1999)

In 1996 Karin Rehnqvist received the Läkerol Arts Award “for her renewal of the relationship between folk music and art music“. The same year she was awarded the “Spelmannen“ prize by the daily newspaper Expressen, and in 1997 she received the Christ Johnson Prize for Solsången. In 2001 she was awarded the Kurt Atterberg Prize.