After his father's death, he ruled jointly with his brother Otto I. They ruled harmoniously and managed significantly to expand the rights and territory of Oldenburg in Frisia.
Christian II managed to end the sovereignty of the Archbishopric of Bremen over Oldenburg; in return he assisted Bremen against the rebellious farmers in Stedingen. He also fought many feuds against his liege lords, against his cousins, and against Hoya.
Marriage and issue
He married Agnes, a daughter of Count Arnold of Altena-Isenburg and had two sons: