Born in 1893, Matthias Kleinheisterkamp enlisted in the Prussian Army in 1914 and served on both the Western and the Eastern Fronts of World War I.

In May 1940, he was put in charge of an infantry regiment within the SS Division Totenkopf under the overall command of Theodor Eicke.

After Eicke was injured in July 1941, Kleinheisterkamp was, for a short time, commander of the Totenkopf, before being replaced by Georg Keppler.

In June 1942, he took over command of the SS Division Nord, leading the unit until December 1943, when he was transferred to the Waffen-SS reserves.

[clarification needed] Kleinheisterkamp was taken prisoner by the Soviet forces on 28 April 1945 near the village of Halbe, south-east of Berlin.