He studied violin, viola, counterpoint and harmony at the Royal Swedish Academy of Music, and later studied viola with Maurice Vieux in Paris and went on to play viola in the Stockholm Concert Society and to study composition with Karl-Birger Blomdahl, Tor Mann and Otto Olsson.
At the beginning of the 1950s he spent a year studying composition in Paris, having already written the first of his seventeen symphonies.
By 1962, with five symphonies completed, his health had deteriorated and his mobility was compromised. Two years later, the Swedish government gave him a guaranteed income for the rest of his life.
After nine months in hospital in 1970, he had to spend most of the rest of the decade in his apartment, where he was able to continue to compose. During this period his music began to become well-known.
Allan Pettersson died on 20 June 1980 in Maria Magdalena parish, Stockholm, aged sixty-eight, leaving his seventeenth symphony and a concerto for viola and orchestra unfinished.
CD Spotlight. The Dead in the Square - Allan Pettersson's Symphony No 12, strongly recommended by Gerald Fenech. 'Christian Lindberg gives a colossal interpretation of this difficult score, where everybody involved is wholly engrossed in Pettersson's unique creation.'