Otfried Hagen was born in Braunschwieg in 1868. His real name was Kirchhoff. Hagen work first as an employee in a company. He started rather late to learn singing. At 26 years, he took lessons in Frankfurt with Franz Krückl, then in Hannover with Gustav Gunz. He made his debut in Heidelberg in 1897 and in 1898 sang in Altenburg, where he married the daughter of the painter Walter. After being in Stettin, Hagen went in 1900 to Magdeburg, where he was classified as Heldentenor. He made his debut there as Tannhäuser. In 1902, he moved to Freiburg. At that time his repertory was made of 32 parts. In 1906, he moved to Munich, where he could not get along with Felix Mottl. In 1909, he only sang Froh during the summer festival and decide to move back to Braunschweig. In 1911, the intendent Julius von Wangenheim was replaced by Baron Egbert von Frankenberg und Ludwigsdorf, who promptly destroyed the opera house through mismanagement. All contracts were not renewed. Hagen moved to Frankfurt. The new intendent lasted 2 years. In 1913 he was replaced by the previous one. Hagen returned in 1914 (September 1) to Braunschweig. After that, he was in Mainz (1916), Würzburg (1917), and Metz (1918). He had to leave Metz after Germany lost the war. Hagen sang one more year and his last review (Tannhäuser) dates from September 1, 1919 in Berlin. It was a failure. Hagen died in Frankfurt am Main on December 8th. 1923.
Reference: Einhard Luther, So viel der Helden, Biographie eines stimmfaches Teil 3, Wagnertenöre der Kaiserzeit, (1871-1918)