Zeljko completed his music education at music academies in Zagreb, Graz and Frankfurt. He has played many concerts during his studies, received numerous awards, performed with various orchestras, including several times with the Zagreb Philharmonic. Whilst he lived in Berlin, he worked intensively on his career as a concert pianist. In that period, among other activities, he performed at the most popular concert halls in Germany. His performances were followed by the media, he was present in both the press and the television, and some of his performances were broadcast live on German TV and German radio stations. ​ Zeljko's repertoire includes the works of Liszt, Chopin, Albeniza, Tchaikovsky, Gershwin, Musorgsk, Brahms .... some of the greatest, most powerful and reputable pieces of piano literature. He directed his focus particularly on Liszt and developed a special way to interpret his music. ​ In addition to his piano repertoire, he is the author of the 13 Sephardic songs for voice and piano. These are especially beautiful and effective songs that he has composed in his own way. Besides playing the piano, Zeljko works as a composer and is interested in other genres apart from the classical music. ​ When he played concerts in Germany, the critics named him "The Poet among the Pianists", and that name has stayed with him and his playing, thus defining him and distinguishing him on the music scene.