Reginald was the son of William II, Duke of Jülich and Maria of Guelders.

He allied himself with King Rupert of Germany, supporting his coronation in Aachen and remained closely connected with the House of Orléans.

This started a new with Holland which ended in 1412 when Reginald ceded Gorinchem for a large sum of money.

Reginald led the traditional feuds of his house, particularly those against the bishops of Utrecht and against Holland and Friesland.

Reginald also stood against the House of Cleves in the Niederrhein area and maintained a lot of influence over Guelders.