From 2011 to 2017, Andreas Gergen was the Director of Opera for the Salzburger Landestheater. His most important work includes directing I AM FROM AUSTRIA, DON CAMILLO & PEPPONE and THE VISIT for the Vereinigte Bühnen Wien, CARMEN at the Felsenreitschule Salzburg festival, and the operetta VIKTORIA UND IHR HUSAR for the Seefestspiele Mörbisch festival (awarded the 2016 Operetta Prize by German radio station BR-Klassik).

He has staged over 100 operas, operettas and musicals, including THE MAGIC FLUTE, HANSEL AND GRETEL and DIE SCHÖNE HELENA (Staatstheater Saarbrücken), MADAME BUTTERFLY, LA TRAVIATA and LA BOHÈME (Haus für Mozart, Salzburg), THE COUNT OF MONTE CHRISTO (premiere, Theater St. Gallen), JEKYLL & HYDE and WEST SIDE STORY (Theater Magdeburg), KISS ME KATE, FRAU LUNA, DIE FLEDERMAUS, THE SOUND OF MUSIC, GREEK, LA CAGE AUX FOLLES, JONNY SPIELT AUF, FIDELIO, IL MONDO DELLA LUNA, SPAMALOT (Salzburg Landestheater), DÄLLEBACH KARI and THE VISIT (both premieres, Thuner Seespiele festival), DIE FLEDERMAUS (Nice Opera), HAIRSPRAY (Munich, Merzig, Tecklenburg), SUNSET BOULEVARD, CATS and REBECCA (Freilichtspiele Tecklenburg), the German-language premieres of THE ADDAMS FAMILY - THE MUSICAL (Musik und Theater Saar) and SHREK - THE MUSICAL (Capitol Theater Düsseldorf), as well as the world premiere of the neighborhood musical ZZAUN! (Staatsoperette Dresden).

As Managing Director and Artistic Director of the Schlossparktheater in Berlin, he staged the European premiere of the Broadway hit PINKELSTADT ("Urinetown - The Musical"), the Kollo operetta WIE EINST IM MAI and DIE DREI VON DER TANKSTELLE by Werner Richard Heymann. He later moved to Stage Entertainment in Hamburg as Artistic Project Manager, where he was involved in developing the musicals DER SCHUH DES MANITU and ICH WAR NOCH NIEMALS IN NEW YORK, among others. For Vereinigte Bühnen Wien, he has directed the highly acclaimed semi-staged concerts of THE PHANTOM OF THE OPERA and LOVE NEVER DIES. In Dortmund's Westfalenhalle, he staged LUTHER – PROJEKT DER 1000 STIMMEN by Michael Kunze and Dieter Falk. From 2011 to 2014 he was Chairman of the Board of the Bundeswettbewerb Gesang Berlin.