After graduating at the Ferenc Liszt Academy of Music in 1970, he was assistant professor at the Brussels Superior Music Conservatory until 1972, where he obtained the Prix Supérieur diploma. From 1975 he taught at the Debrecen school of the Budapest Music Academy. In 1978 he received a scholarship from IRCAM, to work in the instrumental department under the direction of Vinko Globokar.

István Matuz won the 1st prize at the Tenuto Festival Competition in Brussels in 1971, 2nd prize at the International Gaudeamus Competition in Rotterdam in 1971, 3rd prize at the Royan Internation Flute Competition in 1973, and the special prize of the Maria Cannals Flute Competition in Barcelona in 1972. In his repertoire one can find all Hungarian flute compositions, and has been awarded for the premiere of contemporary Hungarian flute works three times, and also for the Hungarian premiere of several foreign works.

He was among the first flutists to use circular breathing (in the 144 minute piece Voces by László Sary, where the flute sounds non-stop), and a new fingering technique, based in permutations. In 1978 he won the 1st prize at the La Rochelle International Competition. In 1977 he was the soloist of concerts conducted by Pierre Boulez and Penderecki. He played in the Tokyo Modern Music Festival, and in 1980 the toured France with the Ensemble Intercontemporain and Pierre Boulez, becoming soloist of this group in 1981.

He has also conducted research at IRCAM. He has made recordings for Erato, and Hungaroton. In 1986 he recorded for he BBC and performed under the direction of Péter Eötvös in Paris (Forum des Halles, Centre Pompidou). Istán Matuz gave courses and master classes in Spain, Germany, Ireland, the former USSR, Japan, Brazil and Cuba.

Awards:
1969, 1970, 1976, 2000 Artisjus Award
1977 Pro Urbe Golden Plaque (Budapest)
1980 Liszt Award
1985 László Lajtha Plaque
1986 Merited Artist
1994 Doppler Award
2004 Knight Cross, the Order of Merit of the Hungarian Republic
2005 Excellent Artist
2010 Kossuth Prize