The son of a businessman, Linder attended elementary, middle and high school in Frankfurt. In June 1918, he volunteered for military service in World War I and served during the closing months of the war with a communications replacement company and in Infantry Regiment 81. After the war, Linder joined the "Freikorps" and fought in the Spartacist uprising in early 1919. He then took courses in civil service and commercial trade. He also studied economics at the University of Frankfurt am Main but broke off his studies in 1920. That year, Linder joined the Finance Administration in Frankfurt as a civil service candidate. He passed his civil service examinations in 1923 and worked in the Finance Department as a senior tax secretary and tax inspector until 1933.