After graduating from high school in Wuppertal in 1924, Gauger studied law and economics. In 1927, he passed his exam for his Diplom degree in economics from the University of Kiel. His first law exam followed in 1930. Afterward, he clerked in Velbert, Wuppertal and Düsseldorf.
Gauger passed his bar exam in 1933 and became a legal assessor in Wuppertal and Mönchengladbach. In 1934, he resigned from the civil service at his own request since he was unable to bring himself to swear the civil servants’ oath to Hitler. Gauger then went to work as a jurist for the First Provisional Church Government of the German Evangelical Church in 1935 and for the Council of the Evangelical Church in Germany in Berlin in 1936.
Gauger was a convinced pacifist. Upon receiving his summons for a physical examination for military service, Gauger attempted suicide in April of 1940. In May, he fled to the Netherlands. He was arrested while attempting to return and, after initially being detained in Düsseldorf, he was transferred to Buchenwald concentration camp in June of 1941. He was brought with a so-called “Transport of Invalids” (code 14f13) from Buchenwald to the Nazi euthanasia center in Pirna-Sonnenstein to be killed and was gassed on July 14, 1941.