Landau was born in Austria. Landau's single mother married a Jewish man, Landau's step-father giving him a surname before dying in 1919. Landau spent time in a Catholic school but was expelled for actively recruiting other students to the Nazi Youth. In 1931 he joined the Nazi party and became a political leader. He was a member of the SA from 1933 to 1934 and then joined the SS. He was imprisoned from 1934 through 1937 for participation in the Dollfuss affair; upon his release he actively engaged in Nazi propaganda activities. He eventually fled legal complications, becoming a German citizen.