At the GDR championships in 1972, Müller won his first national medal with a bronze medal, with A. Hahn in a two-seater behind Horst Hörnlein and Reinhard Bredow as well as Klaus Bonsack and Wolfram Fiedler . In 1974 he was second behind Hans Rinn in the single seater, in 1975 he won the doubles title with Hans-Jürgen Neumann ahead of Rinn / Hahn and Hahn / Hahn. In Oberhof the doubles achieved a total time of 1: 29.56 minutes. In the following year it won bronze again behind these two doubles, and Müller also won the bronze medal in the individual behind Rinn and Dettlef Günther .