A graduate of the Royal Academy of Music, Denmark, he further studied at Conservatorio San Martino (Bologna), Mozarteum (Salzburg), Ecole Normale de Musique (Paris) as well as with maestri such as Franco Ferrara, Carlo Zecchi, Tatjana Nikolajewna and Jakob Gimpel.
In 1992-1999, Niels Muus was a principal conductor at the Tiroler Landestheater, Innsbruck. Carl Nielsen's "Maskarade" and Ruud Langgaard's "Antikrist" - "Critics Choice" for the best opera recording of 2000 in the classical music magazine "Gramophone" are some of the highlights of his activities in the period. In 1999-2003, Niels Muus was engaged as a conductor and a casting director at the Volksoper Wien. Since 2005, Niels Muus is an active music director of Musikfestival Steyr in Upper Austria.
Recognized as an expert in the field of opera, Niels Muus has conducted some major productions worldwide. Among others, notable was a televised production by RAI of Donizetti's "L'Elisir d'amore" from the Macerata Opera Festival (DVD label, ARTHAUS MUSIK), Rossini`s "L`Assedio di Corinto" for the Culture Olympics in Greece, Dvorak's "Rusalka" for the international H.C. Andersen Year in Moscow and Denmark, and Verdi`s "Aida" at the Worker`s Stadium in Beijing - recorded for CCTV.
For Italian opera houses Niels Muus has conducted operas such as Verdi`s "Falstaff", Macbeth", "La Traviata", "Aida" and Nino Rota`s "Il capello di paglia di Firenze".
Singers such as Katia Ricciarelli, Luciane Serra, Erwin Schrott, Daniele Barcellona, Adrian Eröd, Markus Werba, Ildar Abdrazakov, Angela Denoke, Werner Hollweg, Maurizio Muraro, Gregory Kunde, Carmen Giannattasio, Steffen Milling and Wolfgang Koch have sung under his baton.
As a symphonic conductor, Niels Muus has given performances in concert halls such as Berliner Philharmonie, Gewandhaus Leipzig, Academia di Santa Cecilia in Rome, Chicago Symphony Hall, National Arts Center Ottawa, Walt Disney Concert Hall in Los Angeles, Tokyo Bunkakaikan, Tokyo Opera City, and Tivoli Copenhagen conducting orchestras such as MDR Symphony Orchestra, Berliner Symphoniker, Orchestra Arturo Toscanini, Korean Symphony Orchestra, Tokyo Metropolitan Symphony Orchestra, Kansai Philharmonic, Vancouver Opera Orchestra , Czeck Chamber Philharmony, Strauss Symphony of America, Slovak Philharmonic Orchestra and Slovak Radio Symphony Orchestra. His debut at Avery Fisher Hall in New York 2010 was hailed by the American press and he will return to the North American continent for New Years concerts in Canada. The undisputed success of Mozart's "La Clemenza di Tito" at the Oberlin Conservatory 2011 has led to many invitations in the USA.
Since 2010, as the chief conductor of the recently founded Morphing Chamber Orchestra in Vienna, concerts in Vienna, Poland and Moscow are planned for the first season. The release of several CDs: "Wien, Stadt meiner Träume" (Gramola 98908) which is has been released in December 2010. Further CDs will feature world premiere recordings of music by composers, J.Haydn, W.A.Mozart, A. Ivancic and A.M. Zebrowski.
Other discography with Niels Muus as conductor or pianist include CD and DVD productions for the following labels: DEUTSCHE GRAMMOPHON, ARTHAUS MUSIK, GRAMOLA, DANACORD, DYNAMIC, DENON and PREISSER RECORDS WIEN.
As piano accompanist for singers Niels Muus has given recitals in Wigmore Hall, Theatre des Champs Elysees, Berliner Philhamonie, Izumi Hall Osaka and for NHK Television.
Beside conducting activities, Niels Muus is an internationally renowned pedagogue, and has given master classes in institutions such as Conservatorio Monteverdi (Bolzano), Opera Högskolan (Gothenburg), Netherlands Opera Studio (Amsterdam),Opera Studio New National Opera Tokyo, Opera Academy Korean National Opera and has been jury-member in major international competitions such as Belvedere (Vienna), Concorso Toti dal Monte (Rovigo) , Musician of the future (Dublin), and the Composition competition of the Spanish symphony orchestras (AEOS).
Currently he acts as the artistic advisor for Otto Edelmann Society in Vienna and music director for the international research project "The World Opera" – " creating a network of interconnected performance spaces that allow for real-time interaction of performers across high-speed networks." in collaboration with major international research institutes such as Mcgill University (CIRMMT), New York University, Tromsö University and KTH Stockholm.
Niels Muus has received the Jacob Gade Prize 1981 and the Danish Radio Prize 2000.
From 2008-2011 he has been board member of the Fundacion Valparaiso, Madrid.