He was the son of Adolph III, Count of Mark, and Margaret of Jülich (and thus the brother of Margaret of Cleves). After his father"s death in 1394, he became Count of Cleves. Adolph further expanded his influence by marrying a daughter of the Duke of Burgundy.
As a result Cleves was raised to a Duchy by the Holy Roman Emperor, Sigismund, in 1417. By 1423, their dispute resulted in an armed conflict, with Gerhard allying himself with the Archbishop of Cologne. A peace was signed between the two brothers in 1430 and confirmed in 1437.
He was not allowed to call himself Count of Mark, but has to use the title Count zur Mark.
After Gerhard"s death in 1461, the County of Mark and the Duchy of Cleves were reunited again.
