Matjaž Debeljak graduated flute in 1994 at the Academy of Music of the University of Ljubljana, in the class of professor Fedja Rupel. In 2010, he post-graduated with the same professor. He has appeared as a piccolo soloist at many international flute competitions, festivals and concerts (in Zagorje 1996, 2004, 2006, in Belgrade 2004, 2009, 2011, BFS (British Flute Society) in Manchester 2008 and 2012, Flutewise in London 2009, NFA (National Flute Association) 2011, EPF 2011, 2013, Iowa 2012, Riez 2012, Niš 2013, Costa Rica 2013, Grado 2014, 2015, 2018). In July 2009, at the invitation of flutist Sir James Galway, he performed at a piccolo recital in Weggis (Switzerland). Matjaž Debeljak is a piccoloist in the orchestra of the Slovenian National Opera and Ballet in Ljubljana. He leads international masterclasses for piccolo, has recorded two CDs and regularly collaborates with Radio Slovenia. Slovene composers have written twenty compositions for piccolo and dedicated them to him.
Matjaž Debeljak diplomirao je flautu 1994. godine na Akademiji za glazbu u Ljubljani u klasi profesora Fedje Rupela, a godine 2010. završio je i postdiplomski studij kod istog profesora. Kao solist na piccolo flauti sudjelovao je na brojnim međunarodnim flautističkim natjecanjima, festivalima i koncertima (Zagorje 1996, 2004 i 2006, Beograd 2004, 2009 i 2011, BFS (Britanska udruga flautista) 2008 i 2012 u Manchesteru, Flutewise u Londonu 2009, NFA (Američka nacionalna udruga flautista) 2011, EPF 2011, 2013, Iowa 2012, Riez 2012, Niš 2013, Costa Rica 2013, Grado 2014, 2015, 2018). U srpnju 2009. godine, na poziv flautista Sir Jamesa Galwaya, nastupio je na pikolističkom recitalu u Weggisu (Švicarska). Matjaž Debeljak je pikolist orkestra opere Slovenskog narodnog kazališta u Ljubljani. Također, redovito održava pikolističke seminare i majstorske tečajeve, snimio je dva nosača zvuka te surađuje s Radio Slovenijom. Dvadesetak skladbi slovenskih skladatelja za piccolo flautu posvećeno je upravo njemu.