In 1933 Liljefors co-founded Fylkingen, a society for experimental music and arts.
He was also the Chairman of Föreningen Svenska Tonsättare (English: Association of Swedish Composers) from 1947–1963.
These included Harmonilärans grunder med ackordanalys enligt funktionsteorien (C.A.V.
Lundberg, 1937), Harmonisk analys enligt funktionsteorien (C. A. V. Lundholm, 1951), Romantisk harmonik ur pedagogisk synvinkel (Nordiska Musikförlaget, 1969), and Harmonik och sats: Schubert till Ravel (Erika, 1976).
His compositions were characterized by their use of elements of Swedish folk music, particularly with regard to rhythm.