Klaus Bruns studied stage and costume design at the Mozarteum in Salzburg. For almost 30 years, he has worked as a costume designer at theatres including those in Stuttgart, Graz, Frankfurt, Zurich, Cologne, and Leipzig, as well as at the Burgtheater in Vienna, the Thalia Theater Hamburg, the Schaubühne and Deutsches Theater Berlin, and the Residenztheater and Kammerspiele in Munich. He has a long-standing collaboration with Karin Henkel. In opera, he has worked with Barrie Kosky, Michael Talke, Andreas Homoki, Olivier Tambosi, Michael Schulz, Harry Kupfer, Götz Friedrich, and Christof Loy, among others, at the three Berlin opera houses, the Nuremberg Opera, Vlaamse Opera Antwerp, the Bavarian State Opera in Munich, the Leipzig Opera, Teatro Regio Turin, Theater an der Wien, the National Theatres in Mannheim and Weimar, the Rossini Opera Festival in Pesaro, and Dutch National Opera in Amsterdam. His collaborations with Barrie Kosky include "Der Ring des Nibelungen" at the Hanover State Opera; "Rusalka," "Moses und Aron," "Eugene Onegin," "Anatevka," and "The Rise and Fall of the City of Mahagonny" at the Komische Oper Berlin; "La fanciulla del West," "Macbeth," "Die Gezeichneten," "Eugene Onegin," "Boris Godunov," and "Manon Lescaut" at the Zurich Opera House; "Prince Igor" at the Opéra Bastille in Paris; "Fiddler on the Roof" at the Lyric Opera of Chicago; and "Agrippina" at the Hamburg State Opera. For the costumes in Kosky’s Bayreuth production of "Die Meistersinger von Nürnberg," Klaus Bruns was named "Costume Designer of the Year" by Opernwelt magazine in 2018. In 2024, he received the Oper! Award for Best Costume Designer for the world premiere of Alexander Raskatov’s "Animal Farm" in Amsterdam.