Her paternal grandparents were Alfred, 10th Duke of Croÿ (1789–1861) and Princess Eleonore of Salm-Salm (1794–1861).

They had eight daughters and one son: In the mid-1890s, the heir to the Austro-Hungarian throne, Archduke Franz Ferdinand of Austria began visiting Isabella and Friedrich's home.

Eventually, it was discovered that in fact he was courting Countess Sophie Chotek von Wognin, lady-in-waiting to Archduchess Isabella and daughter of Austrian ambassador Bohuslav, Count Chotek of Chotkow and Wognin.

The marriage was morganatic; Sophie was subjected to the indignities of a much lower rank at court than that of her husband, and none of their children could succeed to their father's dynastic honours—all chiefly as a result of Isabella's machinations.

[1] A decade later, Isabella created a similar furore when her nephew, Karl, 13th Prince von Croÿ, sought to marry Nancy Leishman, the charming young daughter of John George Alexander Leishman, United States Ambassador to Germany, the former president of Carnegie Steel.