After his studies in Vienna, the Croatian tenor won first prize at the 1999 Ferruccio Tagliavini Competition in Deutschlandsberg, Austria. Since then, he was engaged at the Bremen Theatre in 2000 and remained a member of the ensemble till 2002.
In 2003-2020 Tomislav Mužek was an ensemblemember of the Croatian National Theatre in Split. Since the autumn 2014 the singer has forged close links with the Semperoper in Dresden, since 2016 he has been a soloist with the Croatian National Theatre in Zagreb.
He has been a welcome guest at the great opera houses, appearing at the Bayerische Staatsoper in Munich, the Staatsoper in Berlin, the Hamburgische Staatsoper, the Semperoper in Dresden, the Volksoper in Vienna, Teatro alla Scala in Milan, Teatro Real de Madrid, Malmö Opera, the Opera House in Daegu (Korea), the Teatro Communale in Florence, Croatian National Theatre in Zagreb, the Théâtre du Capitole in Toulouse and the Opéra National in Paris, Opernhaus Zürich, Theatro Municipal de São Paulo (Brazil). He also has taken part in most important opera festivals like Bayreuth Festival, Munich Opera Festival and Salzburg Easter Festival. Performed extensively on the concert platform, with recitals in Zagreb, Dubrovnik and Bayreuth.
Collaborated with renowned conductors such as Riccardo Muti, Myung Whun Chung, Gianandrea Noseda, Gustavo Adolfo Dudamel, Pierre Boulez, Christian Thielemann, Peter Schneider, Zubin Mehta, Sebastian Weigle, Ivor Bolton, Christopher Hogwood, Vjekoslav Šutej, Ivan Repušić, Manfred Honeck, Bernard Haitink.
In 2022, he made a debut as Lohengrin at the Bolshoi Theatre.
Winner of the Ferruccio Tagliavini Competition in Deutschlandsberg