After studying drama at the University of Vienna (doctorate in 1962) Lehnhoff 1963 assistant director at the Deutsche Oper Berlin with Gustav Rudolf Sellner and Wieland Wagner in Bayreuth.
In 1966, he joined as an assistant at the Metropolitan Opera in New York.
To Lehnhoff important works include Wagner productions, including Tristan und Isolde in 1971 at the Roman Theater Orange with Birgit Nilsson and Jon Vickers (also the new production of this musical drama at the Glyndebourne Festival in 2006 with Nina Stemme). Karl Böhm recommended him in 1972 strongly for Die Frau ohne Shadow in Paris with Christa Ludwig, Walter Berry, Leonie Rysanek and James King.
Early on, he worked with avant-garde stage designers together like Heinz Mack, Günther Uecker, Adolf Luther and Suzan Pitt. Hans Magnus Enzensberger wrote for Lehnhoff staging of Fidelio (Theater am Goetheplatz in Bremen in 1974, features: Uecker) new texts instead of the original dialogues.
Lehnhoff’s Der Ring des Nibelungen in 1984 in San Francisco was in a to Caspar David Friedrich settled oriented amenities. When ring at the Bavarian State Opera in 1987, he worked with Erich Wonder together, was Conductor Wolfgang Sawallisch.
In 1990 Lehnhoff debuted at the Salzburg Festival with Mozart’s Idomeneo; He also staged in Salzburg The subscribed by Franz Schreker (2005) and most recently Richard Strauss Elektra (2010).
Since his time at Wieland Wagner Lehnhoff worked with Anja Silja, particularly in three productions of Leoš Janáček operas at Glyndebourne.
In later years Lehnhoff worked several times at the Festspielhaus Baden-Baden.
His last production in May 2015 was Giacomo Puccini’s Turandot at La Scala in Milan.
German Opera Director Nikolaus Lehnhoff died at 76 from blood cancer.