From 1967 to 1972, he studied history and political sciences at the University of Freiburg, earning a doctoral degree with his dissertation about the strategic failure of Hitler in the Battle of Moscow.

In October 1976, Reinhardt was promoted to lieutenant colonel and served as operations staff officer (G-3) of NATO's Central Army Group (CENTAG) in Heidelberg.

After his promotion to full colonel he served as military assistant to the then minister of defence Manfred Wörner and in 1986 till September 1988 as commander of the Gebirgsjägerbrigade 23 in Bad Reichenhall.

During this time, he also used to be vice president of the Clausewitz Society and a member of the scientific advisory council of the German Military History Research Office (MGFA).

In June 1993, he was promoted to lieutenant general and appointed commander of the 3rd Army Corps in Koblenz, which he also had to disband due to military reforms.

Reinhardt argued that he meant no disrespect to the young soldiers that had died for Germany but found that the ideology of the Waffen-SS was incompatible with the values of democracy.