His early music was influenced by Bartók, Berg, Dallapiccola, Zsolt Durkó, Kurtág, Webern, and the new Polish school. Later, in the 1960s, Boulez, Cage, Stockhausen and oriental philosophy made their mark on his music, and by the 1970s he was writing rather sparse, still, minimalist works. Some of his music has been recorded on Hungaroton.
Jeney taught composition at the Franz Liszt Academy in Budapest, and headed the composition department there from 1995. He died on 28 October 2019, aged seventy-six.