Following the completion of his studies in flute at Cluj Conservatory in 1959, he performed as a flutist with the Sibiu State Philharmonic Orchestra until 1965.

He was editor of the music section of A Hét (1970–73), regular contributor to the program in Hungarian language of the Romanian Radio and Television Corporation.

He played a major role in the development of a Hungarian program with Electrecord, the Romanian state record company.

He was a contributor to volumes like A romániai magyar nemzetiség (Hungarian Ethnicity in Romania), in which he offered a picture of Hungarian musical life in Romania or Zenetudományi Irások (Writings in Musicology), published by Kriterion (1980, 1983), to which he contributed works on the musical aspects of the folkloric and local historical research he conducted during his work.

László is an editor of the commemorative Kodály-volume written by Transylvanian authors entitled Utunk Kodályhoz (Our Road to Kodály; 1984), in which he published a study on the Romanian folksong-adaptations of the celebrated Hungarian composer.