[1] His students include Claus Kühnl, Thomas Hitzlberger, Franz J. Stoiber and Lilo Kunkel.
[2] In a program at the Marktkirche he combined works of his father, the two organ preludes on "Ein feste Burg ist unser Gott" and "Ich weiß, woran ich glaube", and the Partita "Veni Creator Spiritus", with works of his own, the two organ preludes on "Erhalt uns, Herr, bei deinem Wort" and "In dir ist Freude", three compositions paying homage to composers (Hommage à J. S. Bach, Hommage à F. Liszt, Hommage à M. Dupré), his jazzy Mozart Changes and EGATOP, an homage to Erroll Garner, Art Tatum and Oscar Peterson.
The composer comments on Grand Choeur for organ, recorded by Roland Maria Stangier in the Philharmonie Duisburg: Organ compositions entitled Grand Choeur such as those by César Franck, Jacques-Nicolas Lemmens, Théodore Dubois, Alexandre Guilmant und Eugène Gigout are often conceived as preludes and postludes for worship services and traditionally contain registration directions at the start.
[5][6] Gárdonyi´s recent organ piece LIFT HIGH THE CROSS has been premiered by his son Daniel Gárdonyi on 10 February 2019 at St Albans in Hardheim.
Music and books were published by Möseler, Walhall, Ostinato, Zimmermann, Merseburger, Bärenreiter, Heinrichshofen and Schott.