1951 – 1956
Academy of Performing Arts in Bratislava (composition – Ján Cikker)
1957 – 1961
programme adviser of the Slovak Philharmonic Orchestra
1961 – 1968
programme adviser and member of the selective body of the Czechoslovak Radio
he focuses on composition
1985 – 1996
teaches composition at the Academy of Performing Arts in Bratislava
1990 – 1991
chairman of Slovak Music Union and president of the International Music Festival Melos-Ethos
Beside studying at a secondary grammar school he took private lessons of harmony and counterpoint under the tutorship of Ján Zimmer and piano under Rudolf Macudzinski.
"As a composer, Zeljenka followed on from the classics of European modernism. One can feel their influence particularly in his student pieces but also in his later compositions. Although he shook off their influence in his later works, it is beyond dispute that by studying them he acquired a solid schooling in what he afterwards independently developed.
In its initial phases Zeljenka’s creative evolution was contradictory. His style, as it matured, was marked by persistent searching, revaluation, rejection. His creativity took off into various registers in parallel, from neoclassicism, through post-Webern stylisation, to an expressionist gesture which, attempting to convey the broadest possible spectrum of expression, outgrows traditional boundaries and indicates new paths for sound and form.
What the 1960s signify in his music is an evolution of post-Webern conceptions and New Music tendencies. He uses a number of types of sonoristics – varied vocal expression (Auschwitz; Magic Spells; Games; Metamorphoses XV), game-playing with phonemes, qualities of words (Games; Magic Spells), working with echo (Auschwitz) and space (Games). In this period Zeljenka is maturing to the use of untraditional types of notation (Structures; String Quartet No. 1), rational organisation of notes and polymetric articulation of the music material (Quartet for 4 Piano Voices; Polymetric Music). In this period he was intensively engaged in film music, which is associated with the first electronic and electro-acoustic attempts in Slovak music.
On account of the social stagnation of the early 1970s, Zeljenka concentrated more on work for folk ensembles, feeling an affinity with the domestic and European modernism of folk and neo-romantic orientations (the cantata To Sing?Symphony No. 3); he also focused on his own creative premises. Roughly in the period when he was composing Symphony No. 3, he turned his attention to investigating the structural possibilities and capacities of melos and harmony (work with tonal cells containing second procedures). His reductionism of means cleansed and deepened the expression, lending it a meditative tendency (Elegy; Piano Trio). At the same time, Zeljenka may be observed making a synthesising effort and profiting from new experience (Galgenlieder; Mutations; Games and Riddles; Music for Madrigalists and Wind Quintet, etc.). In later evolution, while maintaining continuity he developed his composition further, towards a deeper synthesis of Slovak sources (affinity with folk intonation) and basic classical principles in the areas of structure and harmony. In his final period the rhythmic component became his central concern. An entire series of compositions emerged which have been well appreciated at home and abroad."
(DOHNALOVÁ, Lýdia: Ilja Zeljenka. In: A Hundred Slovak Composers. Eds. Marián Jurík, Peter Zagar. Bratislava : National Music Centre Slovakia, 1998, pp. 289–290.)