Dietrich was the third son of Count Adolf III of the Marck and Margaret of Jülich.
His father had acquired the County of Cleves in 1368 and given this title to his eldest son Adolf.
When Dietrich fell in battle in 1398, he was succeeded as Count of Mark by his elder brother Adolf.
As a result, Gerhard ruled the largest part of Mark, but was to be succeeded by his nephew John.
Gerhard died in 1461 without children and the County of Mark and Duchy of Cleves were reunited again in a personal union under John I.