He belonged to the youngest generation of the students of Kodály; he studied at the Academy of Music between 1938 and 1942 at violin and composition divisions. In his music career he followed the example of his master: his career developed in four fields, as a composer, ethnomusicologist, music critic and music pedagogue. He acquired the nation educating program of Kodály in his early youth already, to which he replied with a deep resonance in the theoretical and practical aspects of his own artistic and scientific career: he also placed the idea of the tradition of Hungarian folk music in the center of his approach.
He lived every day of his life with such a responsibility and spiritual concentration, if he would have sensed the time burdens of his life, tragically narrowly defined, that was exemplified by the short lives of artists with similar fate. As a young entrant he adjusted his artistic-spiritual preparedness to the dual standards of his self-chosen tasks already: parallel with his music training he pursued liberal arts studies in the field of Hungarian ethnography. In his university dissertation written at the age of twenty-three he examined the folk music usage of a social community with the newest monographic method. (A kidei magyarság népzenéje, The Folk Music of the Hungarians at Kide, 1943.)
However as a new field of his interest Járdányi joined the task of the social level education of Hungarian public taste in music in 1943 already. His criticisms, articles, program notes and studies were not only radiant witnesses of his professional knowledge and approach-forming endeavor; but the confession of his high level set of values in one of the most tragic periods of our history. His work as a music critic on the columns of the Forrás (Spring), Szabad Szó (Free Word), Válasz (Response), Valóság (Reality) and other press forums addressed the service of a comprehensive question of nation-community in order to foster musical literacy. The insuppressive truth-expressing demand of his approach as a writer showed through the basic tone of his chronicles: during the apostolate of new Hungarian musical creations, composers as well as the representation of the values of their performing artistry.
He was unwavering in his conviction and unchangeable in the fulfillment of his mission. At times of great historical turning points during his life, at the turn of 1948/1949 as well as at the fall of the revolution in 1956, he did not deny his views, neither then when that had unworthy consequences of condemnation, extrusion and being set aside. He who was a professor at the Academy of Music since the age of twenty-five and was a newly spirited instructor of Hungarian folk music – as the successor of Kodály – besides the courses in music theory, had to bear to be definitively removed from the faculty of the institute as a punishment for his political views.
This negative decision had finally a positive motivating effect on the unfolding of the career of the uniquely prepared creative artist and scientist: possessing his released spiritual powers he undertook a more and more intense scientific role in the Folk Music Researching Team led by Kodály, within which he became the leading personality of research in a few years. He elaborated the new system of the editing of melodies of the Magyar Népzene Tára (Collection of Hungarian Folk Music) that gained international attention. (Magyar népdaltípusok I.-II.; Hungarian Folksong Types Vol. 1-2, 1961).
His oeuvre as a creative artist remained permanent, as well. The unified creed of his oeuvre prevailed steadily in his instrumental and vocal works, in the spirit of creating a new musical art that unfolds on the grounds of the tradition of folk music. However his musical style forms a spiritual community with the compositions of Bartók and Kodály at the level of ideological and stylistic community, the personal conviction of the compositions and individual artistic attitude are more predominantly prevailed in that connection. The creative progress of his chamber works, concertos, choral works and his everlasting Vörösmarty Symphony testifies that.
The memories of the intense creator blessed with and unmatched intuition, the scientist with a scientific preparedness and pedagogue radiating the belief of national-social advancement are indelibly alive in his students. His example has been prevailing up to this day in creative arts and the dual branch of vocal and instrumental education as well as in ethnomusicology (György Kurtág, Helga Szabó, Sándor Devich, and Imre Olsvai).