Born in 1944 in Gjerdrum, Norway. Public debut as a pianist in 1969. Studied composition with Conrad Baden and Finn Mortensen, and received his degree in composition from Oslo Music Conservatory in 1972. Hegdal has taught at the State Academy of Music, and has written and lectured extensively about classical and contemporary music. For several years he was the principal music critic in the newspaper Dagbladet.
During the 70’s Hegdal’s music was characterised by aleatoric principles. His composition technique dealt with procedures for chance operations, the actual music being the result of these operations. Without formal development in the traditional sense the music aimed at unpredictability within the boundaries created by the composer. Later Hegdal’s style of composition has developed towards a greater stylistic openness and a more varied and direct expression, but he is still concerned with the balancing of chance and order in his music.
The composer’s first instrument, the piano, has a prominent position in his list of works. He has also written much chamber music and music for large ensembles and orchestra. His works incorporating voice have been among his most frequently performed, e.g. “Air” and “Make Believe Rag” (both performed at ISCM festivals). In 1985 “Morgensolens sange” for soloists, choir and orchestra was elected “Work of the Year” by the Society of Norwegian Composers. He has received the same distinction three more times, most recently in 1996 for “Grande symphonie de salon” (a work later shortlisted for the Nordic Council Music Award). In 2002 he received the Lindeman Prize. His work "Stort sett" was nominated for the Nordic Council Music Prize 2012.
A project of special importance is “Herbarium” (1974-2002), an attempt to make music approach nature, through a combination of consistent structure and chance. In its final form this work has been performed several times and also recorded, by pianist Herbert Henck. Related works are “Songs and Flowers” and “Decett” (2007), while “Form” (string orchestra) and the clarinet quintet “Veränderungen ohne Thema” represent a freer and more personal expression. “Stort sett” for violin and piano (2005-8) once again deals with the relationship between art and nature. In this comprehensive (all evening) work different approaches to composition are included, from strict organization to improvisation.