From a family of lawyers and diplomats, Christian was the son of the diplomat Christian Wilhelm von Eyben and uncle to Hulderich von Eyben and Weipart Ludwig von Fabrice. After a grand tour with his elder brother Friedrich, in 1723 he entered the service of the prince-bishop of Lübeck Christian August as a squire - the bishop was Laos his godfather. He was an assessor in the Justizkanzlei, the Rentkammer and the Consistory and rose to be chief steward to Christian August's wife Albertine Friederike von Baden-Durlach - his father had entered public life in the service of Albertine's father Frederick VII, Margrave of Baden-Durlach. In 1729 Christian became a canon of Lübeck Cathedral and in 1763 its dean.
Marriage and issue
In Braunschweig Cathedral in 1735 he married Elisabeth Sophia Maria von Hassberge (1717–1782). They had eight children: